Mixtures and formulations comprising an alkyl ammonium edta salt

ABSTRACT

The present invention relates to mixtures comprising: i) at least one lipid and/or at least one oil; and ii) an alkyl ammonium EDTA salt; wherein the mixture has a water content in the range of 0 to 1.0 wt %. The invention further relates to mixtures which are pre-formulations, methods of treatment comprising administration of such pre-formulations, to pre-filled administration devices and kits containing the formulations, to the use of an alkylammonium EDTA salt to reduce the decomposition of the lipid components and/or any active agent contained within the pre-formulation, and to alkyl ammonium EDTA salts as described herein.

FIELD OF THE INVENTION

The present invention relates to mixtures comprising lipids and an antioxidant. The present invention also relates to formulation precursors (pre-formulations) that upon exposure to water or aqueous media, such as body fluids, spontaneously undergo a phase transition thereby forming a controlled release matrix. In particular, the invention relates to mixtures, pre-formulations and compositions having an improved resistance to oxidation.

BACKGROUND TO THE INVENTION

Many bioactive agents including pharmaceuticals, nutrients, vitamins and so forth have a “functional window”. That is to say that there is a range of concentrations over which these agents can be observed to provide some biological effect. Where the concentration in the appropriate part of the body (e.g. locally or as demonstrated by serum concentration) falls below a certain level, no beneficial effect can be attributed to the agent. Similarly, there is generally an upper concentration level above which no further benefit is derived by increasing the concentration. In some cases increasing the concentration above a particular level results in undesirable or even dangerous effects.

Some bioactive agents have a long biological half-life and/or a wide functional window and thus may be administered occasionally, maintaining a functional biological concentration over a substantial period of time (e.g. 6 hours to several days). In other cases the rate of clearance is high and/or the functional window is narrow and thus to maintain a biological concentration within this window regular (or even continuous) doses of a small amount are required. This can be particularly difficult where non-oral routes of administration (e.g. parenteral administration) are desirable or necessary, since self-administration may be difficult and thus cause inconvenience and/or poor compliance. In such cases it would be advantageous for a single administration to provide active agent at a therapeutic level over the whole period during which activity is needed.

Some patients undergoing treatment will typically require a therapeutic dose to be maintained for a considerable period and/or ongoing treatment for many months or years. Thus a depot system allowing loading and controlled release of a larger dose over a longer period would offer a considerable advantage over conventional delivery systems.

Certain of the formulations of the present invention generate a non-lamellar liquid crystalline phase following administration. The use of non-lamellar phase structures (such as liquid crystalline phases) in the delivery of bioactive agents is now relatively well established. A most effective lipid depot system is described in WO2005/117830, and a highly preferred lipid depot is described in that document. However, there remains scope for achieving depot formulations having improved performance in several respects.

Lipid controlled-release delivery systems have been developed with active agents including GLP-1 (WO2006/131730), somatostatin analogues (WO2006/075124), LHRH analogues (WO2006/075125), as well as non-peptides such as buprenorphine (WO2014/016428). Lipid systems are also of value in treatment in their own right and need not include active agents. For example, the FDA approved oral liquid Episil® alleviates the pain caused by oral mucositis and other inflammatory conditions of the mouth by forming a lipid barrier in the oral cavity, but does not require any active agent.

A particularly versatile combination of lipids is glycerol dioleate (GDO) and phosphatidyl choline (PC). However, sustained released formulations can be produced with a wide variety of other lipid components including tocopherol (WO2006/075123), derivatives of sorbitol (WO2016/102683), triglycerides (WO2016/066655), and a variety of phospholipid components including phosphatidyl ethanolamines (WO2013/083459 and WO2013/083460).

Both the lipid components, particularly unsaturated lipids, and any active agent contained in the pre-formulation or sustained release composition are susceptible to oxidation, either during storage or in vivo. It is desirable to decrease the extent of oxidation since oxidation processes may reduce the content of active agent and/or contribute to the formation of unwanted decomposition products. This in turn reduces the shelf life of a product.

One particular factor contributing to oxidation in lipid compositions is the presence of trace amounts of metal ions, particularly transition metals such as iron (Fe). Even when the lipid components are of high purity grade it is often difficult to entirely remove traces of such ions. It is thought that equipment used for the manufacture of lipid formulations commonly includes stainless steel which can leach small amounts of metal ions (particularly Fe) into the mixture. It is therefore common to include an antioxidant in lipid formulations. These generally function by chelating any metal ions, thereby hindering their participation in oxidation processes.

It is a prerequisite that any antioxidant must be soluble in the lipid mixture, e.g. pre-formulation. It is described in WO2012/160213 that a carefully controlled amount of water can be included in lipid pre-formulations without causing a phase change into a liquid crystalline phase. In pre-formulations containing an appreciable aqueous content, it may be possible to include an effective amount of a water-soluble antioxidant such as ascorbic acid, inorganic salts of metal chelators, such as ethylenediaminetetraacetic acid (EDTA) (e.g. sodium or calcium salts) and citric acid. However, for certain active agents it may be necessary to avoid prolonged exposure to water during storage (e.g. because the active agent is moisture sensitive), or a more desirable release profile may be obtained without the inclusion of water in the pre-formulation. The avoidance of water may also reduce the amount of trace metals which may be present, since metal ions are generally more soluble in water than in an organic solvent or lipid environment. In lipid formulations having a low water content it is not possible to use conventional water-soluble antioxidants since these may not have the requisite solubility in a substantially water-free lipid environment. It would therefore be advantageous to provide an antioxidant which is soluble in a substantially water-free lipid environment and which limits or prevents the oxidative degradation of the lipid components of the mixture, e.g. pre-formulation, and any active agent contained within. This is particularly the case for metal chelating agents such as EDTA where the standard inorganic salts (sodium or calcium) are non-soluble or have negligible solubility in non-aqueous environments (e.g. lipid matrices).

WO2010/020794 describes thiolated antioxidants as offering particular advantages in lipid systems and these are also suitable in non-aqueous lipid systems. However, for certain end uses the presence of a thiolated antioxidant may not be acceptable.

This particularly applies, for example, to peptides or proteins having thiolated groups or disulphide bridges. WO2010/020794 also mentions the possibility of including EDTA or the sodium, disodium and calcium disodium salts of EDTA as chelating agent although this is not an option which is exemplified. The present inventors have established that EDTA or the common salts thereof are not soluble to any appreciable extent in the types of lipid formulations described in WO2010/020794, i.e. those based on GDO, SPC and an organic solvent such as ethanol.

It has now surprisingly been established that effective amounts of alkylammonium salts of EDTA can be dissolved in a non-aqueous lipid environment, and that the resulting mixtures, e.g. pre-formulations, are highly resistant to oxidative decomposition during storage. Furthermore, although alkylammonium EDTA salts are believed to have an effect on decreasing the decomposition by the expected mechanism of sequestering metal ions, the present invention may in some embodiments improve oxidation resistance above the level that can be accounted for solely by this mechanism.

The inventors have established that the inclusion of alkylammonium EDTA salts can prevent, or substantially decrease the rate of, oxidation of a wide variety of lipid components and/or active agents contained therein. The inventors have found that the inclusion of alkylammonium EDTA can substantially reduce the loss of assay of active agent in drug samples tested in stability studies and thus increases shelf-life of the drug product. EDTA salts have the advantage that they are inexpensive, easily produced with a wide variety of countercations, and are generally regarded as safe (and are widely used e.g. in pharmaceutical applications).

The stabilizing and shelf-life extending effect of alkylammonium EDTA as found by the inventors may be not only related to the prevention or reduction of oxidation reactions but may be also related to the prevention or reduction of other chemical degradation reactions, e.g. hydrolysis, acylation, deamidation.

SUMMARY OF THE INVENTION

In a first aspect the invention provides a mixture of:

i) at least one lipid and/or at least one oil; and ii) an alkyl ammonium EDTA salt (e.g. comprising an anion of ethylenediaminetetraacetic acid or an analogue thereof); wherein the mixture has a water content in the range of 0 to 1.0 wt %.

In all aspects, ethylenediaminetetraacetic acid analogues and their corresponding anions will typically be as described herein below.

The present invention also provides a pharmaceutical formulation comprising an appropriate combination of lipid excipients, organic solvent, and an alkylammonium EDTA salt, that can be used as a depot-precursor formulation (referred to herein for brevity as a pre-formulation) to address one or more of the needs described above.

In a second aspect, the invention therefore provides a pre-formulation comprising:

i) a lipid mixture comprising:

-   -   a) at least one of a mono-, di- or tri-acyl lipid and/or a         tocopherol;     -   b) optionally at least one phospholipid;     -   c) at least one biocompatible, organic solvent; and         ii) an alkyl ammonium EDTA salt (e.g. comprising an anion of         ethylenediaminetetraacetic acid or an analogue thereof); and         wherein the pre-formulation has a water content in the range of         0 to 1.0 wt %.

In a preferred embodiment the pre-formulation forms, or is capable of forming, at least one liquid crystalline phase structure upon contact with excess aqueous fluid.

As used herein, the “lipid mixture” may be a “lipid controlled-release matrix”.

A particularly preferred combination of components in some embodiments is glycerol dioleate (GDO), phosphatidyl choline (PC), ethanol, and tetrakis(ethanolammonium) EDTA. The pre-formulation of all embodiments may further comprise an active agent, as described herein.

The pre-formulations are highly useful for the controlled and sustained release of an active agent, especially those requiring or benefiting from a very flat release profile and/or minimal “burst” upon administration. In a corresponding embodiment, the invention therefore provides for a mixture of:

i) a lipid mixture comprising:

-   -   a) at least one of a mono-, di- or tri-acyl lipid and/or a         tocopherol;     -   b) optionally at least one phospholipid;     -   c) at least one biocompatible, organic solvent;     -   d) an active agent; and         ii) an alkyl ammonium EDTA salt (e.g. comprising an anion of         ethylenediaminetetraacetic acid or an analogue thereof); and         wherein the mixture has a water content in the range of 0 to 1.0         wt %;

in the manufacture of a pre-formulation for use in the sustained administration of said active agent. In a preferred embodiment, the pre-formulation forms, or is capable of forming, at least one liquid crystalline phase structure upon contact with excess aqueous fluid.

“Bioactive agents”, or “active agents” as referred to herein, may be any compound having a desired biological or physiological effect, such as a peptide, protein, drug, antigen, nutrient, cosmetic, fragrance, flavouring, diagnostic, pharmaceutical, vitamin, or dietary agent and will be formulated at a level sufficient to provide an in vivo concentration at a functional level (including local concentrations for topical compositions). In an embodiment the “active agent” is a natural or synthetic peptide or non-peptide drug Active Pharmaceutical Ingredient (API) which provides a therapeutic, palliative and/or prophylactic effect when administered to a suitable subject (typically being one in need of such an effect).

In a further embodiment, the invention therefore provides a method for the treatment of a human or non-human mammalian subject comprising administering to said subject a pre-formulation as described herein. Such a method may be for the treatment of a human or non-human mammalian subject in need thereof to combat, (e.g. cure, improve, prevent or ameliorate the symptoms of) at least one condition selected from acromegaly, cancers, carcinomas, melanomas, tumours expressing at least one somatostatin receptor, sst(2)-positive tumours, sst(5)-positive tumours, prostate cancers, gastro-entero-pancreatic endocrine tumours, gastro-entero-pancreatic neuroendocrine (GEP NE) tumours (GEP-NET), lung neuroendocrine tumours (lung NET), carcinoid tumours, insulinomas, TSH-secreting pituitary adenomas, gastrinomas, vasoactive intestinal peptide (VIP) tumours and glucagonomas, elevated growth hormone (GH), elevated insulin-like growth factor I (IGF-I), varicial bleeding (especially espohageal), chemotherapy induced gastro intestinal problems (such as diarrhea), lymphorrhea, diabetic retinopathy, thyroid eye disease, obesity, pancreatitis, and related conditions. Such methods are particularly applicable where component d) is at least one somatostatin analogue, as described herein. The preformulations as described herein for use in such methods form a further aspect of the invention.

Correspondingly, in a further aspect, the present invention provides the use of a low viscosity mixture of:

i) a lipid mixture comprising:

-   -   a) at least one of a mono-, di- or tri-acyl lipid and/or a         tocopherol;     -   b) at least one phospho lipid;     -   c) at least one biocompatible, organic solvent; and         ii) an alkylammonium EDTA salt (e.g. comprising an anion of         ethylenediaminetetraacetic acid or an analogue thereof);         wherein the mixture has a water content in the range of 0 to 1.0         wt %; in the manufacture of a low viscosity pre-formulation         medicament for use in the in vivo formation of a depot for         treatment of at least one condition selected from acromegaly,         cancers, carcinomas, melanomas, tumours expressing at least one         somatostatin receptor, sst(2)-positive tumours, sst(5)-positive         tumours, prostate cancers, gastro-entero-pancreatic endocrine         tumours, gastro-entero-pancreatic neuroendocrine (GEP NE)         tumours, lung NE tumours (lung NET), carcinoid tumours,         insulinomas, gastrinomas, vasoactive intestinal peptide (VIP)         tumours and glucagonomas, TSH-secreting pituitary adenomas,         elevated growth hormone (GH), elevated insulin-like growth         factor I (IGF-I), varicial bleeding (especially espohageal),         chemotherapy induced gastro intestinal problems (such as         diarrhea), lymphorrhea, diabetic retinopathy, thyroid eye         disease, obesity, pancreatitis, and related conditions. Such         uses are particularly applicable where component d) is at least         one somatostatin analogue, as described herein.

Certain active agents (e.g. certain peptides) have benefits which are cosmetic rather than (or in addition to) therapeutic in nature. Such effects include weight-loss and/or hunger suppression as well as control over skin or hair pigmentation, hair growth etc. The present invention therefore additionally provides a method of cosmetic treatment of a human or non-human mammalian subject comprising administering to said subject a pre-formulation as described herein. Such a cosmetic method will generally not be a method of therapy (i.e. will not have therapeutic or medical benefit).

One of the advantages of the formulations of the present invention over many other controlled-release compositions is that they are stable to storage in their final form and thus little or no preparation is required at the time of administration. This allows the pre-formulations to be ready-to-administer and also to be supplied in convenient, ready-to-administer form. In a further aspect, the invention therefore provides a pre-filled administration device containing a pre-formulation as described herein. Such a device will generally provide either a single administration or multiple administrations of a composition which will deliver, for example, a dosage of active agent in the range of 1 μg to 15 mg/day, such as 0.1 mg to 15 mg/day or 1 μg to 5 mg/day.

In a further aspect the invention provides a kit comprising said administration device according to the invention.

The kit can optionally contain instructions for subcutaneous or intramuscular administration of said pre-formulation. All pre-formulations described herein are suitable for use in such a kit and may thus be contained therein.

The kits of the invention can optionally include additional administration components such as needles, swabs, and the like and will optionally contain instructions for administration.

In a further aspect the invention provides an alkylammonium EDTA salt comprising at least one alkyl ammonium cation of formula NR¹R²R³R^(4n+) as defined herein, with the proviso that the alkylammonium cation is not trimethylammonium, tetramethylammonium, triethylammonium or tetraethylammonium.

BRIEF SUMMARY OF THE ATTACHED FIGURES

FIG. 1. Octreotide assay of Samples 53-54 as a function of time at storage conditions 25° C./60% RH and 40° C./75% RH.

FIG. 2. Octreotide assay of Samples 55-60 as a function of EDTA concentration (0-750 ppm or 0-0.075 wt %) at three time points (0, 1 and 2 months) after storage at 40° C./75% RH.

FIG. 3. OCT assay in SPC/GDO/EtOH/PG based formulations in the absence (Sample 61) and presence of 100 ppm EDTA (Sample 62) as a function of time at 25° C./60% RH. Formulations were stored in pre-filled glass syringes.

FIG. 4. OCT assay in SPC/GDO/EtOH/PG based formulations as a function of Fe³⁺ concentration in the presence of 0, 25, 100 and 250 ppm EDTA (Samples 63-78) recorded at 1 month of storage at 40° C./75% RH. Formulations were stored in vials with ambient air in the headspace.

FIG. 5. OCT assay data in SPC/GDO/EtOH/PG formulations as a function EDTA:Fe³⁺ molar ratio after 1 month of storage at 40° C./75% RH. Formulations were stored in vials with ambient air in the headspace.

FIG. 6. Assay (a) and Stability Index (b) values of OCT in SPC/GDO/EtOH/PG formulations as a function of time at 40° C./75% RH:without additives (Sample 79, reference), with EDTA(Na) (Sample 80), with EDTA(Na)/ETA (Sample 81), with EDTA (Sample 82), and with EDTA/ETA (Sample 83). Formulations were stored in vials with normal air in the headspace. Except for the reference Sample 79, all formulations also contained 5 ppm Fe³⁺.

FIG. 7. OCT assay in SPC/GDO/EtOH/PG based formulations in the absence (Sample 79) and presence of 100 ppm EDTA solubilized in the lipid formulation by the use of ETA (Sample 84), DiETA (Sample 85) or ethylenediamine (Sample 86) as a function of time at 40° C./75% RH. Formulations were stored in vials with normal air in the headspace.

FIG. 8. OCT assay in SPC/GDO/EtOH/PG (Sample 79—reference without EDTA, and Sample 84 with 100 ppm EDTA) based formulations as a function of time at 40° C./75% RH. Formulations were stored in vials with normal air in the headspace.

FIG. 9. SOM assay in SPC/GDO/EtOH/PG (Sample 89—reference without EDTA and Sample 90 with 100 ppm EDTA) based formulations as a function of time at 40° C./75% RH (a) and 25° C./60% RH (b). Formulations were stored in vials with normal air in the headspace.

FIG. 10. Assay (a) and Stability Index (b) values of GOS in SPC/GDO/EtOH/DMSO formulations without (Sample 93) and with 100 ppm EDTA (Sample 94) as a function of time at 40° C./75% RH. Both formulations contained 5 ppm Fe³⁺ and were stored in vials with normal air in the headspace.

FIG. 11. Assay (a) and Stability Index (b) values of O×Y in SPC/GDO/EtOH/DMSO formulations without (Sample 95) and with 100 ppm EDTA (Sample 96) as a function of time at 40° C./75% RH. Both formulations contained 5 ppm Fe³⁺ and were stored in vials with normal air in the headspace.

FIG. 12. Assay (a) and Stability Index (b) values of GRN in SPC/GDO/EtOH/DMSO formulations without (Sample 97) and with 100 ppm EDTA (Sample 98) as a function of time at 40° C./75% RH. Both formulations contained 5 ppm Fe³⁺ and were stored in vials with normal air in the headspace.

FIG. 13. Assay (a) and Stability Index (b) values of GOS in SPC/GMO/EtOH/DMSO formulations without (Sample 99) and with 100 ppm EDTA (Sample 100) as a function of time at 40° C./75% RH. Both formulations contained 5 ppm Fe³⁺ and were stored in vials with normal air in the headspace.

FIG. 14. Assay (a) and Stability Index (b) values of GOS in SPC/SbOil/EtOH/DMSO formulations without (Sample 101) and with 100 ppm EDTA (Sample 102) as a function of time at 40° C./75% RH. Both formulations contained 5 ppm Fe³⁺ and were stored in vials with normal air in the headspace.

FIG. 15. Vial headspace oxygen concentration for SPC/GDO (50/50 w/w) based formulations without (Samples 103 and 104) and with 100 ppm EDTA (105 and 106) in the absence (a) and presence of 5 ppm Fe³⁺ (b) as a function of time at 60° C./ambient RH. Formulations were stored in vials with normal air in the headspace.

FIG. 16. Vial headspace oxygen concentration for SPC/GDO (35/65 w/w) based formulations without (Samples 107 and 108) and with 100 ppm EDTA (109 and 110) in the absence (a) and presence of 5 ppm Fe³⁺ (b) as a function of time at 60° C./ambient RH. Formulations were stored in vials with normal air in the headspace.

FIG. 17. Vial headspace oxygen concentration for SPC/GDO (50/50 w/w) based formulations without (Samples 103 and 104) and with 100 ppm EDTA (105 and 106) in the absence (a) and presence of 5 ppm Fe³⁺ (b) as a function of time at 40° C./75% RH. Formulations were stored in vials with normal air in the headspace.

FIG. 18. Vial headspace oxygen concentration for SPC/GDO (35/65 w/w) based formulations without (Samples 107 and 108) and with 100 ppm EDTA (109 and 110) in the absence (a) and presence of 5 ppm Fe³⁺ (b) as a function of time at 40° C./75% RH. Formulations were stored in vials with normal air in the headspace.

DETAILED DESCRIPTION OF THE INVENTION

Lipids and oils, particularly those having unsaturated groups, are prone to oxidation. Mixtures which comprise lipids or oils may therefore gradually decrease in purity over time e.g. during storage or use. This is undesirable and may lead to unwanted changes in the physical and/or chemical properties of the mixture. It is particularly important to minimise the amount of breakdown products in mixtures having a pharmaceutical use, since breakdown products may be harmful to a patient and in any case often have to be kept within tightly controlled limits.

Lipids and oils are poorly miscible with water and so the water content of lipids and oils is generally low. It is therefore difficult to formulate lipids or oils with water-soluble antioxidants. It would therefore be desirable to find an antioxidant which could be incorporated with lipids or oils in order to prevent oxidation of the mixture. The present invention addresses these problems.

The mixtures of the present invention are substantially non-aqueous and include at least one lipid and/or oil (component i) and at least one alkylammonium EDTA salt (component ii). In a preferred aspect, the mixture is a pre-formulation. The pre-formulations of the present invention are lipid-based, are substantially non-aqueous and form a depot composition upon contact with an aqueous fluid. As used herein, the terms “formulation” or “pre-formulation” relate to the mixture of components (i) and (ii) (component (i) comprising components (a), (c), and optionally (b) and (d)), which is typically of low viscosity. The term “depot” relates to the composition which is formed upon exposure of the pre-formulation to excess aqueous fluid, e.g. as occurs during numerous parenteral administration routes. Without wishing to be bound by theory, it is thought that this change is brought about at least in part by exchange of solvent (c) for aqueous fluid. The depot typically has a much higher viscosity than the corresponding pre-formulation and provides for the gradual release of any active agent contained within the depot.

In a preferred aspect, the formulations of the present invention generate a non-lamellar phase (e.g. non-lamellar liquid crystalline phase) following administration. The use of non-lamellar phase structures (such as liquid crystalline phases) in the delivery of bioactive agents is now relatively well established. A most effective lipid depot system is described in WO2005/117830, and a suitable lipid matrix for use in the present invention is described in that document, the full disclosure of which is hereby incorporated herein by reference. For a description of the most favourable phase structures of such formulations, attention is drawn to the discussion in WO2005/117830 and particularly to page 29 thereof. Preferably the pre-formulation according to the invention has an L₂ phase (liquid phase) structure or is a liquid solution or molecular solution.

All % are specified by weight herein throughout, unless otherwise indicated. Percent (%) by weight may be abbreviated e.g. as wt %. Furthermore, the % by weight indicated is the % of the total pre-formulation including all of the components indicated herein, unless otherwise indicated. Where a percentage by weight is given in relation to component (d) the weight relates to the amount of free base (e.g. where a salt is used), unless otherwise indicated. In certain Examples, the wt % of a specified salt is provided but is indicated where appropriate and may be readily converted to the corresponding weight of free base.

The pre-formulations can optionally consist of essentially only the components indicated herein (including where appropriate additional optional components indicated herein below and in the attached claims) and in one aspect consist entirely of such components.

The lipid-based pre-formulations described herein comprise lipid mixture (i) which includes lipid components (a) an organic solvent (c), and optionally (b) and (d), and an alkylammonium EDTA salt (ii).

The present inventors have now surprisingly established that by appropriate choice of antioxidant, the oxidation resistance of the lipid and/or oil, and in the case of pre-formulations, any active agent contained in the pre-formulation, can be significantly improved.

Whilst various alkylammonium EDTA salts are known, for instance from Scott and Kyffin (Biochem. J. (1978) 169, 697-701), their use as an antioxidant in lipid systems and compatibility with such formulations has been hitherto unknown. Scott and Kyffin describe the use of soluble EDTA salts in the demineralisation of bone samples, where EDTA acts as a sequestering agent. A particularly suitable solution is said to be 80% aqueous ethanol containing 0.2 M trimethylammonium EDTA. No use in lipid formulations nor solubility in lipids is suggested. The purpose of the EDTA salt in the present invention is as a preservative or stability enhancing agent in lipid formulations, and is very different from that described previously.

Component i)—Lipid and/or Oil

In all embodiments of the invention the mixture comprises at least one lipid and/or oil (component i) and has a water content of 0-1.0 wt %. Mixtures of lipids, mixtures of oils, or mixtures of both lipids and oils may be used as component i).

As used herein, the term “oil” refers to saturated or unsaturated C5-C70 hydrocarbons which are liquid at room temperature and pressure. Preferred oils for use in the invention are saturated or unsaturated C10-C60 hydrocarbons, preferably saturated or unsaturated C10-C40 hydrocarbons.

In an embodiment component i) is an oil which is suitable for use a lubricant. Such oils will typically be saturated C10-C40 hydrocarbons. It is desirable that lubricants are resistant to oxidation, because oxidation tends to increase the viscosity of the lubricant.

In an embodiment component i) comprises, consists essentially of, or consists of at least one fatty acid or fatty acid ester (lipid). Fatty acids/lipids differ from “oils” in that they contain a polar carboxylic acid or ester “head group” with the hydrocarbon chain forming a non-polar “tail” group. Fatty acid esters are esterified fatty acids. Fatty acids or esters used in the present invention may be solid or liquid at room temperature and pressure, preferably liquid.

Examples of non-polar “tail” groups include C₆-C₃₂ alkyl and alkenyl groups, which are typically present as long chain carboxylic acids or the esters thereof. These are often described by reference to the number of carbon atoms and the number of unsaturations in the carbon chain. Thus, CX:Z indicates a hydrocarbon chain having X carbon atoms and Z unsaturations. Examples particularly include lauroyl (C12:0), myristoyl (C14:0), palmitoyl (C16:0), phytanoyl (C16:0), palmitoleoyl (C16:1), stearoyl (C18:0), oleoyl (C18:1), elaidoyl (C18:1), linoleoyl (C18:2), linolenoyl (C18:3), arachidonoyl (C20:4), behenoyl (C22:0) and lignoceroyl (C24:9) groups. For the avoidance of doubt, when reference is made herein to the number of carbon atoms in the “chain” or “tail” this number includes the carbon atom of the —C(O)O—moiety, as is conventional in the art.

Thus, typical non-polar chains are based on the fatty acids of natural ester lipids, including caproic, caprylic, capric, lauric, myristic, palmitic, phytanic, palmitolic, stearic, oleic, elaidic, linoleic, linolenic, arachidonic, behenic or lignoceric acids, or the corresponding alcohols. Preferable non-polar chains are palmitic, stearic, oleic and linoleic acids, particularly oleic acid.

The lipid(s) may be saturated or unsaturated, but preferably comprise at least 1 wt % unsaturated lipid (based on the total lipid content), such as at least 5 wt % (5-100%), at least 15 wt % (15-100%), at least 30 wt % (30-100%), at least 50 wt % (50-100%) or at least 80 wt % (80-100%).

In an embodiment component i) is a single fatty acid/fatty acid ester or mixture of fatty acids/fatty acid esters. Typically component i) will comprise a mixture of saturated and unsaturated fatty acids. In a preferred embodiment the lipid(s) and/or oil(s) are extracted from a natural source.

In an embodiment component i) is an edible lipid such as almond oil, avocado oil, butter, canola oil, castor oil, coconut oil, corn oil, cottonseed oil, flaxseed oil, ghee, lard, linseed oil, macadamia oil, margarine, mustard oil, olive oil, palm oil, peanut oil, pumpkin seed oil, rice bran oil, safflower oil, sesame oil, soybean oil, sunflower oil, tea seed oil, vegetable oil or walnut oil. For the avoidance of doubt, the above edible lipids are “lipids” rather than “oils” in the sense of component (i) because they contain fatty acids, particularly in the form of fatty acid esters, rather than hydrocarbons.

In an embodiment component i) is as defined for component a) or b) as described in subsequent sections.

In a particularly preferred embodiment the mixture consists essentially of, or consists of, components i) and ii).

Pre-Formulations

A pre-formulation is a subcategory of the “mixtures” describe above in which component i) is a lipid mixture and comprises at least one neutral lipid “component a)” and optionally at least one phospholipid “component b)”. Pre-formulations additionally comprise component c) and optionally component d) as described below.

Component a)—Neutral Lipid

Preferable ranges for component a) are 20-90 wt. % of the pre-formulation, preferably 30-70 wt. %, more preferably 33-60% (e.g. 43-60%), particularly 38 to 43%.

Component “a” as indicated herein is at least one mono-, di- or triacyl lipid comprising a polar “head” group and at least one non-polar “tail” group. Alternatively, component a) may comprise or consist of tocopherol(s). In a preferred aspect component a) comprises at least one neutral di-acyl lipid (having no net charge at physiological pH).

As used herein, the term “acyl lipid” relates to a lipid component containing a polyol “head” group and one or more apolar “tail groups”. In certain embodiments the polyol may be glycerol, a sugar or a hexitan such as sorbitan. The term “hexitan” denotes a hexitol of formula HOCH₂(CHOH)₄CH₂OH which has cyclised by formally losing one equivalent of water, to form a five or six membered ring, preferably a five membered furanose ring. Sorbitan is a particularly suitable “head group”, particularly as a component of a mono-acyl lipid component in certain embodiments.

In the case of di- and triacyl lipids, it is most preferred that the lipid component comprises a glycerol head group with two or three apolar tail groups. The two or three non-polar groups may have the same or a differing number of carbon atoms and may each independently be saturated or unsaturated. Examples of non-polar groups include C₆-C₃₂ alkyl and alkenyl groups, which are typically present as the esters of long chain carboxylic acids. These are often described by reference to the number of carbon atoms and the number of unsaturations in the carbon chain. Thus, CX:Z indicates a hydrocarbon chain having X carbon atoms and Z unsaturations. Examples particularly include lauroyl (C12:0), myristoyl (C14:0), palmitoyl (C16:0), phytanoyl (C16:0), palmitoleoyl (C16:1), stearoyl (C18:0), oleoyl (C18:1), elaidoyl (C18:1), linoleoyl (C18:2), linolenoyl (C18:3), arachidonoyl (C20:4), behenoyl (C22:0) and lignoceroyl (C24:9) groups. Thus, typical non-polar chains are based on the fatty acids of natural ester lipids, including caproic, caprylic, capric, lauric, myristic, palmitic, phytanic, palmitolic, stearic, oleic, elaidic, linoleic, linolenic, arachidonic, behenic or lignoceric acids, or the corresponding alcohols. Preferable non-polar chains are palmitic, stearic, oleic and linoleic acids, particularly oleic acid.

Mixtures of any number of monoacyl, diacyl and/or triacyl lipids may be used as component a). Preferably this component will include at least a portion of C18 lipids (e.g. a diacyl glycerol (DAG) having one or more C18:0, C18:1, C18:2 or C18:3 non-polar groups), such as glycerol dioleate (GDO) and/or glycerol dilinoleate (GDL). A highly preferred example is DAG comprising at least 50%, preferably at least 80% and even comprising substantially 100% GDO.

Since GDO and other diacyl glycerols may be derived from natural sources, there is generally a certain proportion of “contaminant” lipid having other chain lengths etc. In this context, “pure” GDO is a di-ester of glycerol and two C18:1 fatty acids. Any other diacyl glycerol is considered to be an impurity. In one aspect, GDO as used herein is thus used to indicate any commercial grade of GDO with concomitant impurities (i.e. GDO of commercial purity). These impurities may be separated and removed by purification but providing the grade is consistent this is rarely necessary. If necessary, however, “GDO” may be essentially chemically pure GDO, such as at least 70% pure, preferably at least 75% pure and more preferably at least 80% pure GDO. Correspondingly, the C18:1 content of GDO referred to herein may be around 80%, preferably at least 85% and more preferably at least 90%.

It will be appreciated that any material used, including component a), may potentially include unavoidable trace impurities of metals, optionally including heavy metals. According to the certificates of analysis for commercially available GDO (e.g. from Croda), a typical maximum concentration of heavy metals (or elemental impurities) in GDO is 5 ppm. Without being bound by theory, the common presence of these metal components and their sequestration in the various aspects of the present invention may be at least partially responsible for the additional stability observed. However, a more common issue may be the presence of iron ions, which may be absorbed from iron-based alloy materials used in handling/storage of the materials.

Component b)—Phospholipid

Optional component “b” in the preferred lipid matrices of the present invention is at least one phospholipid. It is known from WO2016/066655 that lipid slow-release matrices based on triacyl lipids can form depot compositions on exposure to aqueous fluids without the need for a phospholipid component to be present, though a phospholipid may also be present. Thus, in one embodiment component a) comprises, consists or consists essentially of a triacyl lipid(s) and component b) is optional. However, if component a) is greater than 50% mono-acyl or diacyl lipids, or a tocopherol, or mixtures of any of these components, then a phospholipid component b) will preferably be present. In one embodiment, component a) is less than 50% (e.g. 0 to 45%) triacyl lipid (based on the total amount of component a)) and component b) is present (e.g. at 20 to 80 wt % of the pre-formulation).

When present, preferable ranges of component b) are 20-80 wt. % of the pre-formulation, preferably 30-70 wt. %, more preferably 33-55% (e.g. 35-55%), particularly 38 to 43%. When component b) is present, ratios of a:b are typically 40:60 to 70:30, preferably 45:55 to 55:45 and more preferably 40:60 to 54:46, such as 45:55 to 54:46 or 47:53 to 53:47. Ratios of around 50:50 (e.g. 49:51 to 51:49) are highly effective in certain embodiments.

Preferred phospholipid polar “head” groups include phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol. Most preferred are phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE), especially PC. As with component a), this component comprises a polar head group and at least one non-polar tail group. The difference between components a) and b) lies principally in the polar group. The non-polar portions may thus suitably be derived from the fatty acids or corresponding alcohols considered above for component a). The phospholipid will contain two non-polar groups. Again, C18 groups are preferred and may be combined with any other suitable non-polar group, particularly C16 groups.

The phospholipid portion may be derived from a natural source. In the case of PC, suitable sources of phospholipids include egg, heart (e.g. bovine), brain, liver (e.g. bovine) and plant sources including soybean. Such sources may provide one or more constituents of component b, which may comprise any mixture of phospholipids. Any single PC or mixture of PCs from these or other sources may be used, but mixtures comprising soy PC or egg PC are highly suitable. The PC component preferably contains at least 50% soy PC or egg PC, more preferably at least 75% soy PC or egg PC and most preferably essentially pure soy PC or egg PC.

In one embodiment applicable to all aspects of the invention, component b) comprises PC. Preferably the PC is derived from soy. Preferably the PC comprises 18:2 fatty acids as the primary fatty acid component with 16:0 and/or 18:1 as the secondary fatty acid components. These are preferably present in the PC at a ratio of between 1.5:1 and 6:1. PC having approximately 60-65% 18:2, 10 to 20% 16:0, 5-15% 18:1, with the balance predominantly other 16 carbon and 18 carbon fatty acids is preferred and is typical of soy PC.

In an alternative but equally preferred embodiment, the PC component may comprise synthetic dioleoyl PC (DOPC). The use of DOPC may provide increased stability and so will be particularly preferable for compositions needing to be stable to long term storage, and/or having a long release period in vivo. In this embodiment the PC component preferably contains at least 50% synthetic dioleoyl PC, more preferably at least 75% synthetic dioleoyl PC and most preferably essentially pure synthetic dioleoyl PC. Any remaining PC is preferably soy or egg PC as above.

Since the pre-formulations of the invention are to be administered to a subject, possibly with the inclusion of an active agent, it is important that the components are biocompatible. In this regard, the preferred lipid matrices for use in the pre-formulations of the present invention are highly advantageous since tocopherol, PC and acyl glycerols, particularly DAGs, are well tolerated and are broken down in vivo into components that are naturally present in the mammalian body.

It will be appreciated that component b) may include unavoidable trace impurities of heavy metals. According to the certificates of analysis for commercially available soy PC (e.g. from Lipoid), a typical maximum concentration of heavy metals (or elemental impurities) in soy PC is 10 ppm.

Synthetic or highly purified PCs, such as dioleoyl phosphatidyl choline (DOPC) are highly appropriate as all or part of component b). The synthetic dioleoyl PC is most preferably 1,2-dioleoyl-sn-glycero-3-phosphocholine, and other synthetic PC components include DDPC (1,2-Didecanoyl-sn-glycero-3-phosphocholine); DEPC(1,2-Dierucoyl-sn-glycero-3-phosphocholine); DLOPC(1,2-Dilinoleoyl-sn-glycero-3-phosphocholine); DLPC(1,2-Dilauroyl-sn-glycero-3-phosphocholine); DMPC(1,2-Dimyristoyl-sn-glycero-3-phosphocholine); DOPC(1,2-Dioleoyl-sn-glycero-3-phosphocholine); DPPC(1,2-Dipalmitoyl-sn-glycero-3-phosphocholine); DSPC(1,2-Distearoyl-sn-glycero-3-phosphocholine); MPPC(1-Myristoyl-2-palmitoyl-sn-glycero 3-phosphocholine); MSPC(1-Myristoyl-2-stearoyl-sn-glycero-3-phosphocholine); PMPC(1-Palmitoyl-2-myristoyl-sn-glycero-3-phosphocholine); POPC(1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine); PSPC(1-Palmitoyl-2-stearoyl-sn-glycero-3-phosphocholine); SMPC(1-Stearoyl-2-myristoyl-sn-glycero-3-phosphocholine); SOPC(1-Stearoyl-2-oleoyl-sn-glycero-3-phosphocholine); and SPPC(1-Stearoyl-2-palmitoyl-sn-glycero-3-phosphocholine), or any combination thereof.

A particularly favoured combination of components a) and b) are GDO with PC, especially GDO with soy PC and/or DOPC. Appropriate amounts of each component suitable for the combination are those amounts indicated herein for the individual components in any combination. This applies also to any combinations of components indicated herein, where context allows.

Component c)—Biocompatible Organic Solvent

Component c) of the pre-formulations of the invention is at least one biocompatible organic solvent. Since the pre-formulation is to generate a depot composition following administration (e.g. in vivo), typically upon contact with excess aqueous fluid, it is desirable that this solvent be tolerable to the subject and be capable of mixing with the aqueous fluid, and/or diffusing or dissolving out of the pre-formulation into the aqueous fluid. Solvents having at least moderate water solubility are thus preferred. As will be described hereinafter, component c) may include a polar co-solvent.

Component c) comprises or consists of at least one solvent selected from the group consisting of: alcohols, amines, amides or esters. Preferably component c) comprises at least a mono-alcoholic solvent. Most preferably component c) comprises ethanol, propanol, iso-propanol, or mixtures thereof. It is particularly preferred the component c) comprises or consists of ethanol. Component c) may comprise or consist of a mono-alcoholic solvent, preferably ethanol, and a polar co-solvent. Mixtures comprising or consisting of ethanol and propylene glycol are also highly preferred.

The amount of component c) in the pre-formulation will have a considerable effect upon several features. In particular, the viscosity and the rate (and duration) of release may alter significantly with the solvent level. The amount of solvent will thus be at least sufficient to provide a low viscosity mixture but will additionally be determined so as to provide the desired release rate. Typically a level of 1 to 30%, particularly 2 to 20% solvent will provide suitable release and viscosity properties. In some embodiments, levels of 2 to 18%, such as 2 to 16%, especially 2 to 15% are preferred.

As indicated above, the amount of component c) in the pre-formulations of the invention will be at least sufficient to provide a low viscosity mixture (e.g. a molecular solution) of components a), c) and ii) (components b) and d) being optional as described herein), and will be easily determined for any particular combination of components by standard methods.

The phase behaviour may be analysed by techniques such as visual observation in combination with polarized light microscopy, X-ray scattering and diffraction techniques, nuclear magnetic resonance, and cryo-transmission electron microscopy (cryo-TEM) to look for solutions, L₂ or L₃ phases, or liquid crystalline phases or as in the case of cryoTEM, dispersed fragments of such phases. Viscosity may be measured directly by standard means. As described above, an appropriate practical viscosity is that which can effectively be syringed and particularly sterile filtered. This will be assessed easily as indicated herein.

A highly preferred combination for components a), b) and c) is GDO, soy PC and ethanol, especially GDO, soy PC and mixtures of ethanol and propylene glycol. As indicated above, appropriate amounts of each component suitable for the combination are those amounts indicated herein for the individual components, in any combination.

It is preferable that little or none of component c) contains halogen substituted hydrocarbons since these tend to have lower biocompatibility.

Component c) as used herein may be a single solvent or a mixture of suitable solvents but will generally be of low viscosity. The viscosity of the “low viscosity” solvent component c) (single solvent or mixture) should typically be no more than 18 mPas at 20° C. This is preferably no more than 15 mPas, more preferably no more than 10 mPas and most preferably no more than 7 mPas at 20° C.

It is described in WO2012/160213 that the addition of a polar solvent in addition to a mono-alcoholic solvent results in numerous advantages including reduced viscosity and reduced active agent burst profile. In addition to the preferred aspects described previously for component c), in one particularly preferred embodiment component c) comprises a mono-alcoholic solvent and a polar co-solvent. The term “polar co-solvent” as used herein defines a solvent having a dielectric constant (diel) of at least 28 at 25° C., more preferably at least 30 at 25° C. but is not water or any aqueous fluid. Highly suitable examples include propylene glycol (diel ˜32), and N-methyl-2-pyrrolidone (NMP, diel ˜32). The preferred levels of component c) recited herein apply equally to mixtures of mono-alcoholic solvent and a polar co-solvent unless context permits otherwise.

In a particularly preferred embodiment component c) comprises, consists essentially of, or consists of a mixture of a mono-alcoholic solvent and a polar co-solvent. The polar co-solvent may in one embodiment be a di-alcoholic C3-C6 organic solvent, i.e. a C3-C6 organic solvent comprising two hydroxy groups. The di-alcoholic solvent is preferably propylene glycol. When present, a polar co-solvent is included at a level of 2 to 12 wt. % of the pre-formulation, such as 3 to 10 wt. %, especially 4 to 9 wt. %. This level is counted as part of the ranges recited above for component c). In an embodiment component c) comprises, consists essentially of, or consists of a mixture of ethanol and propylene glycol (PG).

Where both an organic mono-alcoholic solvent and a polar co-solvent are present, e.g. ethanol and PG, the ratio of mono-alcoholic solvent to polar co-solvent solvent is preferably in the range 20:80 to 70:30, preferably 30:70 to 70:30 (w/w), more preferably 40:60 to 60:40. Approximately equal amounts of mono- and di-alcoholic components are highly appropriate.

In an especially preferred embodiment component c) is present at a level of 1 to 30% and comprises, consists or consists essentially of a mixture of ethanol and PG, wherein the ratio of ethanol to PG (w/w) is in the range of 30:70 to 70:30, preferably 40:60 to 60:40. More preferably component c) is present at a range of 5 to 15 wt % or 8 to 18 wt %, most preferably 8-18% wt % and is a mixture of ethanol and PG in a ratio of 40:60 to 60:40 (w/w).

For the avoidance of doubt, even where a polar co-solvent is present in the pre-formulations of the present invention, the total water level will remain as described in the various embodiments herein (e.g. 0.1 to 1.0 wt %).

Component ii)—Alkylammonium Salt

Component ii) is an alkylammonium salt comprising an anion of EDTA (“ethylenediamine tetraacetic acid” or “edetic acid”) or an anion of an EDTA analogue as described below, and at least one alkylammonium cation of Formula (I):

NR¹R²R³R^(4a+)  (I)

wherein each R¹-R⁴ is independently H, or a linear or branched C1-10 group (as described herein), with the proviso that at least one of R¹-R⁴ is not H.

Typically, and preferably, n=1. However, for ammonium salts containing more than one nitrogen atom, such as ethylenediamine (NH₂CH₂CH₂NH₂) it may be possible for a mixture of +1 and +2 cations to exist (i.e. NH₂CH₂CH₂NH₃ ²⁺ and NH₃CH₂CH₂NH₃ ²⁺). To a certain extent the formation of polycationic species may be prevented by providing an excess of the precursor amine as described below.

However, the person skilled in the art will appreciate when the formation of mixed cations is a possibility.

Each of R¹ to R⁴ may be the same or different, with the proviso that at least one of R¹ to R⁴ is not H. Preferably all of the substituent groups R¹ to R⁴ which are not H are the same. Preferred cations are therefore NRH₃ ⁺, NR₂H₂ ⁺ and NR₃H⁺ or NR₄+ wherein the “R” groups are the same. Primary, secondary and tertiary ammonium cations are preferred to quaternary cations as the former can be easily prepared by combining the appropriate amine with EDTA as described below.

Each of R¹ to R⁴ is independently H or a linear or branched C1-10 alkyl, alkenyl or alkynyl group, preferably C1-C5. Most preferably each of R¹ to R⁴ is a linear or branched C1-5 alkyl group, especially a linear C1-C5 or C1-C3 alkyl group.

Each R¹ to R⁴ may independently be further substituted with one or more OH or NH₂ (or NH₃+) groups. In an embodiment, for a substituent R containing m carbon atoms, the substituent may contain a maximum of m−1 OH and/or NH2 groups per substituent. For instance, if R1 is C8 then R1 may contain up to 7 OH groups, especially one OH unit attached to each carbon atom other than the carbon atom directly joined to the ammonium N atom. This embodiment is of particular relevance to the case in which the alkylammonium cation is derived from an aminopolyol (e.g. meglumine (MeNHCH₂(CHOH)₄CH₂OH)). As an alternative example, if R1 is C3 then R1 may contain up to 2 OH groups, such as serinol (NH₂CH(CH₂OH)₂). In an embodiment at least one of R′—R⁴ is a linear C1-C6 group substituted with at least one OH or NH₂ group.

In one embodiment any two of the groups R1 to R4 taken together form a C4-C8, preferably C4-C6 ring, which may optionally contain one or more exocyclic OH or NH2 groups. If any two of the groups R¹ to R⁴ together form a ring then a single endocyclic 0 or NH unit may also be present. In particular, it is envisaged that morpholine salts may be used (i.e. if any two of R¹ to R⁴ together form a six-membered C4 ring containing one endocyclic 0 atom). In this embodiment two of the groups R¹ to R⁴ along with N together form a morpholine ring, while the remaining groups R¹ to R⁴ have the definition above.

Particularly preferred alkylammonium cations include those derived from N-protonation, or in a less preferred embodiment N-alkylation, of an amine selected from:

-   Ethanolamine “ETA” (NH₂(CH₂CH₂OH)); -   Diethanolamine “DiETA” (NH(CH₂CH₂OH)₂); -   meglumine (NH(CH₃)CH₂(CHOH)₄CH2OH)); -   tris-hydroxymethylamine “TRIS” (N(CH₂OH)₃); -   ethylenediamine (NH₂CH₂CH₂NH₂); or -   serinol (NH₂CH(CH₂OH)₂).

It is preferred that the mass of the alkylammonium cation of Formula (I) is below 500 amu, preferably below 350, especially below 250 amu. Salts of EDTA containing the ethanolammonium ion (HOCH₂CH₂NH₃ ⁺) are particularly preferred in the invention. It is most preferred that the EDTA salt is a salt of EDTA with ethanolamine (ETA), preferably EDTA with ETA only.

In an embodiment the invention relates to EDTA salts comprising an anion of EDTA and at least one alkylammonium cation of Formula (I) as previously described, with the proviso that the alkylammonium cation is not trimethylammonium, tetramethylammonium, triethylammonium or tetraethylammonium.

The alkylammonium cation is thought to aid in increasing the lipid solubility the EDTA salt relative to a conventional metal (inorganic) EDTA salt such as disodium EDTA. As EDTA contains four carboxylic acid units the alkylammonium salt may comprise up to four ammonium cations and a tetraanionic EDTA anion.

As used herein, the term “EDTA” may represent ethylenediaminetetraacetic acid as such. Alternatively, EDTA as indicated herein may include both ethylenediaminetetraacetic acid itself and EDTA analogues. “EDTA” herein thus includes “EDTA and analogues thereof” whenever context allows. Suitable EDTA analogues are those containing at least one glycinate unit (i.e. the unit —NCH₂COO—) within the molecule, preferably at least 2, at least 3 or at least 4 glycinate units. Suitable EDTA analogues include:

Iminodiacetic acid (IDA) —(NH(CH₂CO₂H)₂; Nitrilotriacetic acid (NTA) —N(CH₂CO₂H)₃; Pentetic acid* —N(CH₂CO₂H)₂CH₂CH₂N(CH₂CO₂H)CH₂CH₂N(CH₂CO₂H)₂; Egtazic acid —N(CH₂CO₂H)₂CH₂CH₂OCH₂CH₂OCH₂CH₂N(CH₂CO₂H)₂ NOTA —[N(CH₂CO₂H)CH₂CH₂]₃ DOTA —[N(CH₂CO₂H)CH₂CH₂]₄ * Also known as “DTPA”

In an embodiment the EDTA analogue has the structure indicated in Formula (II) below:

wherein n is 1-10, preferably 1-5, especially 1, 2 or 3; wherein X is CH₂, O or NR₄ wherein R₁, R₂, R₃ and R₄ are each individually H or CH₂CO₂H, preferably CH₂CO₂H; or wherein R₁ and R₃ together represent a covalent bond (i.e. the EDTA analogue is cyclic) and R₂ and R₄ are each individually H or CH₂CO₂H, preferably CH₂CO₂H.

Amounts of EDTA and ratios of EDTA to (d) defined herein apply equally to EDTA and EDTA analogues. In all embodiments it is preferred that EDTA is used as the counterion in component (ii).

Formation of EDTA Salt

The EDTA salt may be pre-formed and dissolved or dispersed in one or more of the components prior to forming the mixture, e.g. pre-formulation, or may be formed in situ. In situ formation is generally preferred for simplicity of operation. A suitable method for preparing the alkylammonium EDTA salt involves dissolving EDTA (acid form) and the requisite alkylamine (base) in the solvent component (c), or in a solvent which is a precursor to (or sub-component of) the solvent component (c), and providing mixing until the solids are fully dissolved. In the case of mixtures other than pre-formulations as defined herein, the EDTA salt may be pre-formed and dissolved or dispersed in component i).

The inventors have established that as a general rule, for a mono-amine at least 3.0, preferably at least 3.5 (e.g. 3.5 to 10) molar equivalents of amine (which is a precursor to the ammonium salt) are required relative to the amount of EDTA in order to solubilize the salt in the solvent component (c). As is described in the examples, the minimum ratio between the amine and EDTA necessary to solubilize the salt varies depending on the specific choice of alkylammonium salt. However, an appropriate molar ratio can be achieved by experimentation by simply observing at what molar excess of alkylamine the solid EDTA fully dissolves in the solvent. In an embodiment, a greater than stoichiometric ratio of amine is added than is formally needed to form the tetraamonium EDTA salt. For instance, as is described in the following examples, efficient solubilisation of EDTA using TRIS may require 5.0 or more equivalents of amine.

For certain di-amines or tri-amines the molar ratio to achieve adequate EDTA salt solubility may not be as high as for a mono-amine. For polyamines (diamines, triamines etc), such as NH₂CH₂CH₂NH₂, the required molar ratio may be lower than that for a mono-amine. Suitable levels for polyamines may be 2.0 or more (e.g. 2.0 to 4.0), or 2.5 or more. Again, suitable levels can be found by optimisation. As a guide, the molar equivalents of amine discussed above may represent the molar ratio of mono-amine to EDTA or the ratio of amine moieties to EDTA where the amine (or mixture of amines) has more than one amine moiety in the molecule (either individually or on average for a mixture).

There is no upper limit on the number of equivalents of amine which may be present, although it will be appreciated that typically no more amine should be included than is necessary to ensure efficient solubilisation. A typical practical limit may be 20 equivalents, preferably 10 equivalents.

The inventors have established that in order to form the alkylammonium EDTA salt, it is necessary to begin with the acid form of EDTA rather than the commonly used disodium EDTA (EDTA(Na)). Neither EDTA (edetic acid) nor EDTA(Na) are soluble in suitable/preferred solvents (e.g. EtOH/PG) without an alkylamine (e.g. ETA), even after several months of mixing. Surprisingly, EDTA(Na) is insoluble in EtOH/PG even in the presence of ETA.

A typical procedure for producing the salt therefore involves dissolving the free tetraacid EDTA (which may be a hydrate) in the solvent (c), or in a solvent which is a precursor to the solvent component (c), which comprises at least a mono-alcoholic solvent such as ethanol, and may also comprise a polar co-solvent as previously described, preferably in a mixture of ethanol and PG. The requisite number of equivalents of alkylamine are then added and the mixture is agitated, e.g. by end-over-end rotation or magnetic stirring until the EDTA is dissolved, as can be established by visual observation. 24 h of mixing is usually adequate to ensure efficient solubility, e.g. in the case of the formation of an ETA/EDTA salt.

It is also within the scope of the invention to form the salt in a solvent which is a precursor to the solvent component (c). By “precursor” it is meant that the solvent in which the EDTA salt is formed is not identical to the final composition of solvent component (c), but that the content of solvent(s) in the precursor can be adjusted to arrive at the final composition of the solvent (c) in the pre-formulation. As an example, the salt may be formed in a mixture of EtOH:PG (1:2) and additional ethanol added during or after salt formation in order to reach a final composition of EtOH:PG (1:1) for component (c).

Ratio of Alkylamine to EDTA

The inventors have surprisingly established that above a certain ratio of alkylamine:EDTA the chemical stability of the active agent in the pre-formulation begins to decrease. This may be a result of reaction between the excess alkylamine and the active agent, either directly or via degradation products. Accordingly, it is preferred that the amount of alkylamine chosen is sufficient to fully solubilize all of the EDTA in the solvent component (c) but is not significantly beyond this level. It is preferred that the amount of alkylamine included is no more than 2 times the required level to achieve complete solubility, preferably no more than 1.5 times, preferably no more than 1.2 times. The amount of alkylamine necessary to fully solubilize ETDA in the solvent component (c) can be established by the methods described previously.

In an embodiment component (ii) comprises an alkylammonium counterion having only one amino or alkylamino group and the ratio of EDTA:the total of said alkylammonium counterion and any amine free base thereof in the pre-formulation is 1:≥3.0; preferably 1:≥3.5, most preferably in the range of 1:3.0 to 1:10.

In an embodiment component (ii) comprises an alkylammonium counterion having two or more amino and/or alkylamino groups, wherein the ratio of EDTA:the total of said alkylammonium counterion and any amine free base thereof in the pre-formulation is 1:≥2.0; preferably in the range of 1:2.0 to 1:4.0.

In a particularly preferred aspect the EDTA salt is an ETA salt of EDTA. The inventors have established that in this embodiment in order to fully solubilise EDTA in the solvent component (c) (e.g. a mixture of EtOH/PG 50:50) it is necessary to include around at least 3.5 molar equivalents of ETA relative to the amount of EDTA. Accordingly, the amount of ETA to EDTA is preferably no more than 7:1. The equivalents of ETA to EDTA are preferably in the range of 3.5 to 7 (mol/mol), preferably 3.5 to 5, most preferably 3.5 to 4.5. Most preferably 4 equivalents of ETA are used relative to the amount of EDTA (mol/mol).

Amount of EDTA Salt

The level of alkylammonium EDTA salt is chosen to ensure appropriate stability of the components of the lipid vehicle and active agent (if any) for the storage duration required and under the chosen storage conditions. Factors to be considered when determining appropriate amounts of alkylammonium EDTA salt include: the reactivity of the lipid components and active agent (if any), the loading of active agent (if any), the molecular mass of the active agent, storage conditions (oxygen content, humidity, temperature), the duration of oxidative protection required and the concentration of metal ions present in the pre-formulation (which may catalyse decomposition processes).

In order to suppress the catalytic activity of metals, e.g. Fe, the pre-formulation will typically include the EDTA salt at a level such that the ratio of EDTA salt to metal (e.g Fe, especially in the form of Fe(II) and Fe(III) ions) is at least around 2:1 (mol/mol), i.e. the EDTA salt is present in at least a 2 times molar excess. In a typical procedure the molar ratio will be based upon the maximum estimated metal ion (especially Fe ion) concentration and EDTA provided in a ratio of around 2:1 to this maximum estimate. The result in practice will then be 2:3 or greater molar ratio of EDTA to metal (e.g. Fe ions).

The inventors have established that there is a preferred level of EDTA, above which no advantage in terms of oxidation resistance of the mixture, e.g. pre-formulation is observed, and indeed the stability may be somewhat reduced. This is influenced by the amount of metal ions (e.g. Fe ions) present in the formulation as is discussed in detail in the “Experimental” section. However, in general a suitable amount of EDTA salt in the pre-formulation (calculated in terms of EDTA free acid) will be 0.001-0.02 wt % (10-200 ppm), preferably 0.001-0.015 wt % (10-150 ppm), especially 0.002-0.015 wt % (20-150 ppm). A particularly preferred level is 0.005-0.015 wt. % (50-150 ppm), most preferably 0.008-0.012 wt. % (80-120 ppm). A level of 100 ppm is suitable for protecting against up to 10 ppm of metal (iron equivalents) which is reasonable for ensuring appropriate drug product robustness.

In certain embodiments, the levels of EDTA (based on the weight of EDTA alone and not including the amine countercations) may range from 0.001 to 0.8 wt % (10 to 8000 ppm), 0.002 to 0.5 wt % (20 to 5000 ppm), 0.005 to 0.2 wt % (50 to 2000 ppm) or 0.01 to 0.1 wt % (100 to 1000 ppm) of the pre-formulation. In certain embodiments the level of EDTA may range from 0.001 to 0.050 wt % (10 to 500 ppm) of the mixture, e.g. pre-formulation, preferably 0.002 to 0.030 wt % (20 to 300 ppm) of the mixture.

The level of alkylamine to be added can be established once the optimum ratio of alkylamine to EDTA is found, as described in preceding sections.

In an embodiment the ratio of (ii) to (d) is in the range 1:1 to 1:5000 (w/w), preferably 1:1 to 1:500 (w/w), preferably in the range of 1:50 to 1:300.

Water Content

The inclusion of EDTA salts containing an alkylammonium ion of Formula (I) allows for an antioxidant to be included in the mixture, e.g. pre-formulation, at low levels of water. It is however extremely difficult to completely eliminate all traces of water (especially from the raw materials). Even if essentially water-free formulations could be achieved, pre-formulations will typically be stored in ready-to-use form, e.g. in syringes and possibly under refrigerated conditions. Syringes are often not completely air-tight meaning that the level of water in the pre-formulation may increase to an appreciable level over time, e.g. over months, even if the initial level of water is insignificant.

The initial absolute level of water in the mixture, e.g. pre-formulation, is between 0 to 1.0 wt. %. Preferably the water content is less than 1.0 wt. %, preferably less than 0.8 wt %, preferably less than 0.5 wt %. Most preferably, the level of water is in the range of 0.1 to 0.9 wt. %, especially 0.2 to 0.8 wt. %. These levels refer to the absolute level of water and not added levels of water. Any unavoidable trace of water present within components a), b) or c) is included in this stated level of water. After 3 months of storage, the absolute water level is preferably no more than 1.5 wt %. Absolute levels of water can be measured by methods well known in the art such as Karl Fischer titration. In particular, the water content is preferably measured according to the procedure in United States Pharmacopoeia (USP 40-NF 35, USP <921> Water determination, Method Ia.

Component d)—Active Agent

The pre-formulations of the present invention may contain one or more peptide or non-peptide active agents. It is emphasised that the surprising discovery that the oxidation of lipid pre-formulations having low levels of water (no more than 1.0%), and optionally any active agent contained therein can be reduced by the inclusion of particular EDTA salts herein described, is of very general applicability and therefore the nature of the bioactive agent is not particularly critical to the working of the invention. Indeed, since oxidation of the lipid components is reduced by the method of the invention, advantages of the present invention may be obtained independently of the nature or even presence of any active agent.

It is envisaged that the invention is applicable to lipid pre-formulations containing any bioactive agent of interest. Bioactive agents may be any compound having a desired biological or physiological effect, such as a peptide, protein, drug, antigen, nutrient, cosmetic, fragrance, flavouring, diagnostic, pharmaceutical, vitamin, or dietary agent and will be formulated at a level sufficient to provide an in vivo concentration at a functional level (including local concentrations for topical compositions). Most preferred active agents are pharmaceutical agents including drugs, vaccines, and diagnostic agents. An especially preferred class of active agents is somatostatins and somatostatin analogues.

Examples of drugs which may be delivered by the composition of the present invention include, but are not limited to, antibacterial agents, immune modulating agents, including immunostimulants and immunosuppressants, anticancer and/or antiviral drugs such as nucleoside analogues, paclitaxel and derivatives thereof, anti inflammatory drugs/agents, such as non-steroidal anti inflammatory drugs and corticosteroids, cardiovascular drugs including cholesterol lowering and blood-pressure lowing agents, analgesics, anti-emetics including histamine H1, NK1 and 5-HT₃ receptor antagonists, corticosteroids and cannabinoids, antipsychotics and antidepressants including serotonin uptake inhibitors, prostaglandins and derivatives, vaccines, and bone modulators. Diagnostic agents include radionuclide labelled compounds and contrast agents including X-ray, ultrasound and MRI contrast enhancing agents. Nutrients include vitamins, coenzymes, dietary supplements etc.

Particularly suitable active agents include those which would normally have a short residence time in the body due to rapid breakdown or excretion and those with poor oral bioavailability. These include peptide, protein and nucleic acid based active agents, hormones and other naturally occurring agents in their native or modified forms. By administering such agents in the form of a depot composition formed from the pre-formulation of the present invention, the agents are provided at a sustained level for a length of time which may stretch to days, weeks or even several months in spite of having rapid clearance rates. This offers obvious advantages in terms of stability and patient compliance over dosing multiple times each day for the same period. In one preferred embodiment, the active agent thus has a biological half life (upon entry into the blood stream) of less than 1 day, preferably less than 12 hours and more preferably less than 6 hours. In some cases this may be as low as 1-3 hours or less. Suitable agents are also those with poor oral bioavailability relative to that achieved by injection, for where the active agent also or alternatively has a bioavailability of below 20%, or preferably below 2%, especially below 0.2%, and most preferably below 0.1% in oral formulations.

The amount of bioactive agent to be formulated with the pre-formulations of the present invention will depend upon the functional dose and the period during which the depot composition formed upon administration is to provide sustained release. Typically, the dose formulated for a particular agent will be around the equivalent of the normal daily dose multiplied by the number of days the pre-formulation is to provide release. Evidently this amount will need to be tailored to take into account any adverse effects of a large dose at the beginning of treatment and so this will generally be the maximum dose used. The precise amount suitable in any case will readily be determined by suitable experimentation.

In an embodiment the pre-formulation of the invention may comprise one or more peptide active agents. Peptide active agents may comprise 5 to 60 natural and/or synthetic amino acids, especially 5 to 50 or 5 to 40 amino acids.

Peptide and protein based active agents include human and veterinary drugs selected from the group consisting of adrenocorticotropic hormone (ACTH) and its fragments, angiotensin and its related peptides, antibodies and their fragments, antigens and their fragments, atrial natriuretic peptides, bioadhesive peptides, bradykinins and their related peptides, calcitonin peptides including calcitonin and amylin and their related peptides, vasoactive intestinal peptides (VIP) including growth hormone releasing hormone (GHRH), glucagon, and secretin, opioid peptides including proopiomelanocortin (POMC) peptides, enkephalin pentapeptides, prodynorphin peptides and related peptides, pancreatic polypeptide-related peptides like neuropeptide (NPY), peptide YY (PYY), pancreatic polypeptide (PPY), cell surface receptor protein fragments, chemotactic peptides, cyclosporins, cytokines, dynorphins and their related peptides, endorphins and P-lidotropin fragments, enkephalin and their related proteins, enzyme inhibitors, immunostimulating peptides and polyaminoacids, fibronectin fragments and their related peptides, gastrointestinal peptides, gonadotrophin-releasing hormone (GnRH) agonists and antagonist, glucagon-like peptides 1 and 2, growth hormone releasing peptides, immunostimulating peptides, insulins and insulin-like growth factors, interleukins, luthenizing hormone releasing hormones (LHRH) and their related peptides (which are equivalent to GnRH agonists as described below), melanocortin receptor agonists and antagonists, melanocyte stimulating hormones and their related peptides, nuclear localization signal related peptides, neurotensins and their related peptides, neurotransmitter peptides, opioid peptides, oxytocins, vasopressins and their related peptides, parathyroid hormone and its fragments, protein kinases and their related peptides, somatostatins and their related peptides, substance P and its related peptides, transforming growth factors (TGF) and their related peptides, tumor necrosis factor fragments, toxins and toxoids and functional peptides such as anticancer peptides including angiostatins, antihypertension peptides, anti-blood clotting peptides, and antimicrobial peptides; selected from the group consisting of proteins such as immunoglobulins, angiogenins, bone morphogenic proteins, chemokines, colony stimulating factors (CSF), cytokines, growth factors, interferons (Type I and II), interleukins, leptins, leukaemia inhibitory factors, stem cell factors, transforming growth factors and tumor necrosis factors. An interesting class of bioactive agents suitable for the invention are peptide hormones, including those of the: glycoprotein hormone family (the gonadotropins (LH, FSH, hCG), thyroid stimulating hormone (TSH); proopiomelanocortin (POMC) family, adrenocorticotropic hormone (ACTH); the posterior pituitary hormones including vasopressin and oxytocin, the growth hormone family including growth hormone (GH), human chorionic somatomammotropin (hCS), prolactin (PRL), the pancreatic polypeptide family including PP, PYY and NPY; melanin-concentrating hormone, (MCH); the orexins; gastrointestinal hormones and peptides including GLP-1 and GIP; ghrelin and obestatin; adipose tissue hormones and cytokines including leptin, adiponectin, and resistin; natriuretic hormones; parathyroid hormone (PTH); the calcitonin family with calcitonin and amylin; the pancreatic hormones including insulin, glucagon and somatostatin. All synthetic peptides designed to have similar receptor affinity spectrums as the above mentioned peptides are also very suitable for the invention.

A further considerable advantage of the depot compositions of the present invention is that active agents are released gradually over long periods without the need for repeated dosing. The compositions are thus highly suitable for situations where patient compliance is difficult, unreliable or where a level dosage is highly important, such as mood-altering actives, those actives with a narrow therapeutic window, and those administered to children or to people whose lifestyle is incompatible with a reliable dosing regime and for “lifestyle” actives where the inconvenience of repeated dosing might outweigh the benefit of the active. Particular classes of actives for which this aspect offers a particular advantage include contraceptives, hormones including contraceptive hormones, and particularly hormones used in children such as growth hormone, anti-addictive agents, and drugs used in treatment of poorly compliant populations, such as patients suffering from schizophrenia, Alzheimer, or Parkinson's disease, anti-depressants and anticonvulsants.

Cationic peptides and proteins are particularly suitable for use where a portion of the pre-formulation comprises an anionic amphiphile such as a fatty acid or anionic lipid, including phosphatidic acid, phosphatidylglycerol, phosphatidylserine. In this embodiment, preferred peptides or proteins include octreotide, lanreotide, calcitonin, oxytocin, interferon-beta and -gamma, interleukins 4, 5, 7 and 8 and other peptides or proteins having an isoelectric point above pH 7, especially above pH 8.

In one preferred aspect of the present invention, the composition of the invention is such that a reversed micellar cubic (I₂) phase, or a mixed phase including I₂ phase is formed upon exposure to aqueous fluids and a polar active agent is included in the composition. Particularly suitable polar active agents include peptide and protein actives, oligo nucleotides, and small water soluble actives, including those listed above. Of particular interest in this aspect are the peptide octreotide and other somatostatin related peptides, interferons alpha and beta, glucagon-like peptide 1 and glucagon-like peptide 2 receptor agonists, leuprorelin and other GnRH agonists, abarelix and other GnRH antagonists, granisetron and ondansetron and other 5-HT₃ receptor antagonists.

GnRH Analogues

GnRH analogues form one particular class of active agents which may be included in formulations of the present invention.

Gonadotropin-releasing hormone agonists (GnRH agonists) are synthetic peptides modelled after the hypothalamic neurohormone GnRH that interacts with the gonadotropin-releasing hormone receptor to elicit its biologic response, the release of the pituitary hormones follicle stimulating hormone (FSH) and luteinizing hormone (LH). GnRH agonists are useful in treatment of cancers that are hormonally sensitive and where a hypogonadal state decreases the chances of a recurrence. Thus they are commonly employed in the medical management of prostate cancer and have been used in patients with breast cancer. Other indication areas include treatment of delaying puberty in individuals with precocious puberty, management of female disorders that are dependent on estrogen productions. In addition, women with menorrhagia, endometriosis, adenomyosis, or uterine fibroids may receive GnRH agonists to suppress ovarian activity and induce a hypoestrogenic state.

Gonadotropin-releasing hormone receptor agonists (GnRH-RAs), such as leuprolide (or leuprorelin), goserelin, histrelin, triptorelin, buserelin, deslorelin, nafarelin and related peptides are used or indicated for the treatment of a variety of conditions where they are typically administered over an extended period. GnRH-RAs form a preferred group of active agents for use in the present invention.

GnRH itself is a post-translationally modified decapeptide of structure pyro-Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH₂ (GnRH-I). Two natural varients are also known, GNRH-II having 5-His, 7-Trp, 8-Tyr substitutions and GnRH III having 7-Trp, 8-Leu. Several peptide analogues with agonistic properties are known, most of which have the 10-Gly-NH₂ replaced with N-Et-NH₂. Fertirelin has 10-Gly to N-Et-NH₂ substitution only, while analogues having additional substitutions over GnRH-I include Leuprorelin (Leuprolide), (6-D-Leu), Buserelin (6-Ser(Bu^(t))), Histrelin (6-d-His(Imbz1)), Deslorelin (6-d-Trp). Another common nona-peptide agonist is Goserelin which is substituted with 6-Ser(Bu^(t)) and has 10-Gly-NH₂ replaced by AzaGly-NH₂. Narafelin (6-d-Nal) and Triptorelin (6-d-Trp) both retain the 10-Gly-NH₂ group. The structures of the two most common GnRH agonists (Leuprolide and Goserelin) are shown below as acetate salts.

Leuprolide: pyro-Glu-His-Trp-Ser-Tyr-D-Leu-Leu-Arg-Pro-N-Et-NH₂ (acetate)

Goserelin: pyro-Glu-His-Trp-Ser-Tyr-D-Ser(Bu^(t))-Leu-Arg-Pro-Azgly-NH₂ (acetate)

A small number of GnRH antagonists are also known, again based on the GnRH-I structure. These include Abarelix (D-Ala-D-Phe-D-Ala-Ser-Tyr-D-Asp-Leu-Lys(^(i)Pr)-Pro-D-Ala), Antarelix (D-Nal-D-Phe-D-Pal-Ser-Phe-D-Hcit-Leu-Lys(^(i)Pr)-Pro-D-Ala); Cetrorelix (D-Nal-D-Phe-D-Pal-Ser-Tyr-D-Cit-Leu-Arg-Pro-D-Ala), Ganirelix (D-Nal-D-Phe-D-Pal-Ser-Tyr-D-hArg-Leu-HArg-Pro-D-Ala), Itrelix (D-Nal-D-Phe-D-Pal-Ser-NicLys-D-NicLys-Leu-Lys(^(i)Pr)-Pro-D-Ala) and Nal-Glu (D-Nal-D-Phe-D-Pal-Ser-D-Glu-D-Glu-Leu-Arg-Pro-D-Ala).

Administration of single doses of a GnRH agonist, such as leuprolide, stimulates pituitary release of gonadotropins (i.e., LH and FSH), resulting in increased serum LH and FSH concentrations and stimulation of ovarian and testicular steroidogenesis. Transient increases in serum testosterone and dihydrotestosterone (DHT) in males and in serum estrone and estradiol concentrations in premenopausal females are observed during initial therapy with single daily doses of the drug.

Although the effect of a potent GnRH agonist during short-term and/or intermittent therapy is stimulation of steroidogenesis, the principal effect of the drug in animals and humans during long-term administration is inhibition of gonadotropin secretion and suppression of ovarian and testicular steroidogenesis. The exact mechanism(s) of action has not been fully elucidated, but continuous therapy with a GnRH agonist apparently produces a decrease in the number of pituitary GnRH and/or testicular LH receptors, resulting in pituitary and/or testicular desensitization, respectively. The drug does not appear to affect receptor affinity for gonadotropins. Leuprolide's mechanism of action may also involve inhibition and/or induction of enzymes that control steroidogenesis. Other mechanisms of action may include secretion of an LH molecule with altered biologic activity or impairment of normal pulsatile patterns of LH and FSH secretion.

A number of serious medical indications are related to and/or affected by the concentration of gonadal steroid hormones. These include certain neoplastic diseases, including cancers, especially of the breast and prostate, and benign prostatic hypertrophy; premature or delayed puberty in adolescents; hirsuitism; alzheimer's disease; and certain conditions relating to the reproductive system, such as hypogonadism, anovulation, amenorrhea, oligospermia, endometriosis, leiomyomata (uterine fibroids), premenstrual syndrome, and polycystic ovarian disease. Control of this system is also important in in vitro fertilisation methods.

Although treatment with a GnRH agonist might be expected to exacerbate conditions affected by gonadal steroid hormone concentration, the down-regulation effect discussed above results in the decrease of these hormones to castrate level if therapy is continued for around 2 weeks or longer. As a result, hormone-receptive tumours such as certain prostate and breast cancer, as well as precocious puberty and many of the other conditions mentioned above can be improved or palliated by long-term GnRH agonist therapy.

In an embodiment, pre-formulations of the present invention contain one or more GnRH analogues. Since GnRH is a peptide hormone, typical GnRH analogues will be peptides, especially of 12 or fewer amino acids. Preferably such peptides will be structurally related to GnRH I, II and/or III, and/or one or more of the known analogues, including those listed here. Peptides may contain only amino acids selected from those 20 α-amino acids indicated in the genetic code, or more preferably may contain their isomers and other natural and non-natural amino acids, (generally α, β or γ amino acids) and their analogues and derivatives. Preferred amino acids include those listed above as constituents of the known GnRH analogues.

Amino acid derivatives are especially useful at the termini of the peptides, where the terminal amino or carboxylate group may be substituted by or with any other functional group such as hydroxy, alkoxy, carboxy, ester, amide, thio, amido, amino, alkyl amino, di- or tri-alkyl amino, alkyl (by which is meant, herein throughout C₁-C₁₂ alkyl, preferably C₁-C₆ alkyl e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-, sec- or t-butyl etc.), aryl (e.g phenyl, benzyl, napthyl etc) or other functional groups, preferably with at least one heteroatom and preferably having no more than 10 atoms in total, more preferably no more than 6.

Particularly preferred GnRH analogues are constrained peptides of 6 to 12 alpha-amino acids, of which particular examples include those indicated above, and particularly leuprolide and goserelin, of the sequences indicated above.

By “GnRH analogues”, as used herein is indicated any GnRH agonist or antagonist, preferably peptides, peptide derivatives or peptide analogues. Peptide derived GnRH agonists are most preferred, such as those indicated above and especially leuprolide or goserelin.

Where present, the GnRH analogue will generally be formulated as 0.02 to 12% by weight of the total pre-formulation (based on the amount of free base). Typical values will be 0.1 to 10%, preferably 0.2 to 8% and more preferably 0.5 to 6%. A GnRH analogue content of around 1-5% is most preferable.

Doses of the GnRH analogue suitable for inclusion in the pre-formulation, and thus the volume of formulation used will depend upon the release rate (as controlled, for example by the solvent type and amount use) and release duration, as well as the desired therapeutic level, the activity of the specific agent, and the rate of clearance of the particular active chosen. Typically an amount of 0.1 to 500 mg per dose would be suitable for providing a therapeutic level for between 7 and 180 days. This will preferably be 1 to 200 mg. For leuprolide or goserelin, the level will typically be around 1 to 120 mg (e.g. for a 30 to 180 day duration). Preferably, the amount of leuprolide will be around 0.02 to 1 mg per day between injections, for depots designed for release over 30 days to 1 year, preferably 3 to 6 months. Evidently, the stability of the active and linearity of the release rate will mean that the loading to duration may not be a linear relationship. A depot administered every 30 days might have, for example 2 to 30 mg or a 90 day depot have 6 to 90 mg of active, such as one of the GnRH analogues indicated herein.

Somatostatin Analogues

Somatostatin analogues form one particular class of active agents which may be included in formulations of the present invention. Somatostatins (Growth Hormone Release Inhibiting Factors, SSTs) are natural peptide hormones with a wide distribution in animals, acting as neurotransmitters in the central nervous system, and having diverse paracrine/autocrine regulatory effects on several tissues. Two biologically active products are known in higher species, SST-14 and SST-28, the latter being a congener of SST-14 extended at the N-terminus.

SST-14 is a 14 residue cyclic peptide hormone having the sequence Ala-Gly-Cys-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Cys, where the two cysteine residues are connected by a disulphide bridge to generate a type II β-turn at the key binding sequence of Phe-Trp-Lys-Thr. The biological half-life of natural SST-14 is very short (1-3 minutes) and so it is not, in itself, a viable therapeutic in current formulations, but an increasing number of somatostatin receptor agonists are becoming available with higher activities and/or longer clearance times in vivo.

Somatostatin receptor agonists (SRAs), such as SST-14, SST-28, octreotide, lanreotide, vapreotide, pasireotide (SOM 230) and related peptides, are used or indicated in the treatment of a variety of conditions where they are typically administered over an extended period. SRAs form a preferred group of active agents for use in the present invention.

Octreotide, for example, is the synthetic octapeptide with sequence D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Thr-ol (2-7 disulphide bridge) and is typically administered as an acetate salt. This SST-14 derivative retains the key Phe-(D)Trp-Lys-Thr β-turn required for in vivo SST-like activity but, in contrast to the natural hormone, has a terminal half-life of around 1.7 hours. Octreotide is used in treatment of conditions including carcinoid tumours and acromegaly, and is typically administered over a sustained period of weeks, or more commonly many months or years. Somatostatin receptor agonists are of particular interest for the treatment of many different types of cancers since a wide variety of tumours are found to express somatostatin receptors (SSTRs). There are five known types of SSTRs (SSTR1-SSTR5), showing equally high affinity for SST-14. The most investigated somatostatin receptor agonists, including octreotide, show high selectivity for SSTR2 and SSTR5; thus, octreotide is of particular interest for the treatment of tumours expressing these types of receptors.

The most common “simple” formulation of Octreotide is “Sandostatin” (RTM) from Novartis. This is an aqueous solution for subcutaneous (s.c) injection, and a 100 μg dose reaches a peak concentration of 5.2 ng/ml at 0.4 hours post injection. The duration of action can be up to 12 hours but s.c. dosing is generally carried out every 8 hours. Evidently, s.c. injection 3 times daily for periods of months or years is not an ideal dosing regime.

Following a single subcutaneous dose of pasireotide, human plasma levels typically peak quickly, at around 15 minutes to 1 hour after dosing, with an initial half-life of 2-3 hours following that peak. Although clearance half-life is greater for later phases of the decline, it is clear that the Cmax/Cave for such a delivery will be rather high.

Pasireotide LAR is a long acting formulation of pasireotide which addresses some of the above issues. However, this is a polymer microparticle based system with the inherent limitations of such a system, as are known in the art and described herein above.

Carcinoid tumours are intestinal tumour arising from specialised cells with paracrine functions (APUD cells). The primary tumour is commonly in the appendix, where it is clinically benign. Secondary, metastatic, intestinal carcinoid tumours secrete excessive amounts of vasoactive substances, including serotonin, bradykinin, histamine, prostaglandins, and polypeptide hormones. The clinical result is carcinoid syndrome (a syndrome of episodic cutaneous flushing, cyanosis, abdominal cramps, and diarrhea in a patient with valvular heart disease and, less commonly, asthma and arthropathy). These tumours may grow anywhere in the gastrointestinal tract (and in the lungs) with approximately 90% in the appendix. The remainder occurs in the ileum, stomach, colon or rectum. Currently, treatment of carcinoid syndrome starts with i.v. bolus injection followed by i.v. infusion. When sufficient effect on symptoms has been established, treatment with a depot formulation of octreotide formulated in ploy lactic-co-glycolic acid (PLGA) microspheres is started. However, during the first two weeks or more after injection of the depot, daily s.c. injections with octreotide are recommended to compensate for the slow release from the PLGA spheres.

Certain of the pre-formulations of the present invention contain salts of one or more somatostatin receptor agonists (which are preferred examples of the peptide actives, which in turn are intended by any reference to “active agents” herein). Since SST-14 is a peptide hormone, typical somatostatin receptor agonists will be peptides, especially of 14 or fewer amino acids. Preferably such peptides will be structurally constrained such as by being cyclic and/or having at least one intra-molecular cross-link. Amide, ester or particularly disulphide crosslinks are highly suitable. Preferred constrained peptides will exhibit a type-2 β turn. Such a turn is present in the key region of somatostatin. Peptides may contain only amino acids selected from those 20 α-amino acids indicated in the genetic code, or more preferably may contain their isomers and other natural and non-natural amino acids, (generally α, β or γ, L- or D-amino acids) and their analogues and derivatives. The term “somatostatin receptor agonist” as used herein may optionally also encompass SST-14 and/or SST-28, since these are viable peptide actives when formulated as salts in the very high performance slow-release formulations described herein.

Amino acid derivatives and amino acids not normally used for protein synthesis are especially useful at the termini of the peptides, where the terminal amino or carboxylate group may be substituted by or with any other functional group such as hydroxy, alkoxy, ester, amide, thio, amino, alkyl amino, di- or tri-alkyl amino, alkyl (by which is meant, herein throughout C₁-C₁₈ alkyl, preferably C₁-C₈ alkyl e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-, sec- or t-butyl etc.), aryl (e.g phenyl, benzyl, napthyl etc) or other functional groups, preferably with at least one heteroatom and preferably having no more than 10 atoms in total, more preferably no more than 6.

Particularly preferred somatostatin receptor agonists are constrained peptides of 6 to 10 α-amino acids, of which particular examples include octreotide, lanreotide (of sequence NH₂-(D)Naph-Cys-Tyr-(D)Trp-Lys-Val-Cys-Thr-CONH₂ and its cyclic derivative of sequence NH₂-(D)Naph-Cys-Tyr-(D)Phe-Lys-Val-Cys-Thr-CONH₂ both having a Cys-Cys intramolecular disulphide crosslink), pasireotide (aka SOM 230) and vapreotide. When present, the somatostatin receptor agonist will generally be formulated as 0.1 to 12% by weight of the total formulation (based on the amount of free base). Typical values will be 0.1 to 10%, 0.5 to 9%, preferably 1 to 8% and more preferably 1 to 7%. A somatostatin receptor agonist content of 2-6% is most preferable.

Doses of the somatostatin receptor agonist suitable for inclusion in the formulation, and thus the volume of formulation used, will depend upon the release rate (as controlled, for example by the solvent type and amount use) and release duration, as well as the desired therapeutic level, the activity and the rate of clearance of the particular active chosen. Typically an amount of 1 to 500 mg per dose would be suitable for providing a therapeutic level for between 7 and 90 days. This will preferably be 5 to 300 mg. For octreotide, the level will typically be around 10 to 180 mg (e.g. for a 30 to 90 day duration). Preferably, the amount of octreotide will be around 0.2 to 3 mg per day between injections. Thus a depot administered every 30 days would have 6 to 90 mg or a 90 day depot have 18 to 270 mg of octreotide.

For Pasireotide, the dosage would typically be an amount of around 0.05 to 40 mg per week of depot duration, preferably 0.1 to 20 mg per week duration (e.g. 1 to 5 mg per week) for a duration of 1 to 24 weeks, preferably 2 to 16 (e.g. 3, 4, 8, 10 or 12) weeks. In an alternative embodiment the pre-formulation may be formulated for dosing weekly (e.g. every 7±1 days). A total dose of 0.05 to 250 mg of Pasireotide per dose would be suitable for providing a therapeutic level for between 7 and 168 days. This will preferably be 0.1 to 200 mg, e.g. 0.2 to 150 mg, 0.1 to 100 mg, 20 to 160 mg etc. Evidently, the stability of the active and effects on the release rate will mean that the loading to duration may not be a linear relationship. A depot administered every 30 days might have, for example 0.2 to 20 mg of Pasireotide, or a 90 day depot might have 30 to 60 mg of Pasireotide.

Where the salt of a peptide active agent, such as an SRA, is used in the formulations of the present invention, this will be a biologically tolerable salt. Suitable salts include the acetate, pamoate, chloride or bromide salts. The chloride salt is most preferred.

Other Active Agents

In another embodiment the pre-formulation comprises an active agent which is not a somatostatin or a somatostatin analogue. For example, the peptide active agent may be a peptide which does not interact as either agonist or antagonist at any of the SST(1) to SST(5) receptors (especially the corresponding human receptors).

Typically, such pre-formulations will not contain any somatostatin or a somatostatin analogue active agent. That is to say, an active agent is present which does not fall within the scope of somatostatin analogues described in the preceding section. In particular, in this embodiment the pre-formulation may comprise an active agent which is not selected from endogenous somatostatins, SST-14, SST-28, octreotide, lanreotide, vapreotide or pasireotide or salts thereof. These peptides are preferably excluded from the pre-formulations of this embodiment. It is preferred that the pre-formulation is free of somatostatins, somatostatin receptor agonists and somatostatin analogues.

Other active agents which may be contained in pre-formulations of the invention include:

GnRH antagonists, e.g. cetrorelix, ganirelix, abarelix, degarelix;

GLP-1 and analogues thereof, e.g. GLP-1(7-37), GLP-1(7-36) amide, liraglutide, semaglutide, exenatide, and lixisenatide (AVE0010); glucagon-like peptide 2 agonists (GLP-2) and analogues thereof, e.g. GLP-2 and elsiglutide (ZP1846); DPPIV inhibitors; sodium/glucose cotransporter 2 (SGLT2) inhibitors.

Other peptides suitable for the invention include: angiopeptin, angiotensin I, II, III, antileukinate, anti-inflammatory peptide 2, aprotinin, bradykinin, bombesin, calcitonin, calcitriol, cholecystokinin (CCK), colony-stimulating factor, corticotropin-releasing factor, C-Peptide, DDAVP, dermorphin-derived tetrapeptide (TAPS), dynorphin, endorphins, endostatin, endothelin, endothelin-1, enkephalins, epidermal growth factor, erythropoietin, fibroblast growth factor, follicle stimulating hormone, follistatin, follitropin, galanin, galanin-like peptide, galectin-1, gastrin, gastrin-releasing peptide, G-CSF, ghrelin, glial-derived neurotrophic factor, GM-CSF, granulocyte colony-stimulating factor, growth hormone, growth hormone-releasing factor, hepatocyte growth factor, insulin, insulin-like growth factors-I and I, interferons, interleukins, leptin, leukemia inhibitory factor, melanocortin 1,2,3,4, melanocyte-stimulating hormone metastin, monocyte chemotactic protein-1 (MCP-1), morphiceptin, NEP1-40, neuropeptide Y, neuropeptide W, orexin-A & orexin-B, oxytocin p21-Cipl/WAF-1, TAT fusion protein, parathyroid hormone, pigment epithelium-derived growth factor (PEDF), peptide, peptide, prorenin handle region, peptide YY (3-36), platelet activating factor, platelet-derived growth factor, prorenin decapeptide, protegrin-1, PR39, prolactin, relaxin, secretin, substance P, tumor necrosis factor, urocortin, vascular endothelial growth factor, vasoactive intestinal polypeptide, vasopressin.

The short elimination half-life of opioids such as morphine, hydromorphone, and oxycodone require that these agents be administered frequently to achieve around-the-clock analgesia, which makes them excellent candidates for long acting release formulations. Fentanyl and buprenorphine undergo significant first-pass metabolism and lacks sufficient bioavailability after oral administration. Together with their high potency, fentanyl and buprenorphine are excellent candidates for the long acting injection depot formulation of the invention. Sufentanil, remifentanil, oxymorphone, dimorphone, dihydroetorphine, diacetylmorphine are other potent opioid receptor agonists suitable for use in the invention.

Buprenorphine is also used for maintenance treatment of opioid addiction as well as potentially also cocaine and amphetamine and met-amphetamine addiction, where current sublingual buprenorphine formulations suffer from low bioavailability, high variability and limited effect duration, resulting in issues with unpredictable dose response and withdrawal symptoms, particularly in mornings. These issues effectively addressed by using the injection depot formulation of the invention, as are problems with misuse and misdirection where the need for high sublingual doses are exploited by injection, where the effect is significantly higher for the same dose, thus facilitating misuse of the drug. Similarly, opioid antagonists can be used for treating addiction using a convenient injection depot system as provided by the invention. Suitable opiate antagonists for use with the invention are naloxone, nalmefene, and naltrexone.

Antipsychotics, including risperidone, iloperidone, paliperidone, olanzapine, asenapine, ziprazidone and aripiprazole are also highly suitable for the invention in view of the potential for improved treatment compliance by patients, as well as by providing stable plasma levels over time. Similarly, the invention is useful in the treatment of dementia, Alzheimer's disease and Parkinson's disease, which adversely affect cognition. Suitable active ingredients include donepezil, rivastigmine, galantamine, and emantine, rasagilin and pramipexol.

Another group of active agents which may be contained in pre-formulations of the invention are 5HT₃ antagonists. Where the active agent comprises a 5HT₃ antagonist or second generation 5HT₃ antagonist, this is preferably selected from ondansetron, tropisetron, granisetron, dolasetron, palonosetron, alosetron, cilansetron and/or ramosetron or mixtures thereof. Doses of the 5HT₃ antagonist suitable for inclusion in the formulation, and thus the volume of formulation used will depend upon the release rate (as controlled, for example by the solvent type and amount use) and release duration, as well as the desired therapeutic level, the activity of the specific agent, and the rate of clearance of the particular active chosen. Typically an amount of 1 to 500 mg per dose would be suitable for providing a therapeutic level for between 5 and 90 days. This will preferably be 1 to 300 mg. For granisetron, the level will typically be around 10 to 180 mg (e.g. for a 3 to 60 day duration). Preferably, the amount of granisetron will be around 0.2 to 3 mg per day between injections, for depots designed for release over 30 days to 1 year, preferably 3 to 6 months. Evidently, the stability of the active and linearity of the release rate will mean that the loading to duration may not be a linear relationship. A depot administered every 30 days might have, for example 2 to 30 mg or a 90 day depot have 6 to 90 mg of active.

In a preferred embodiment the pre-formulation comprises at least one active agent which is not a somatostatin receptor agonist. Preferably the pre-formulation is free from somatostatin receptor agonists. Thus, the pre-formulation may be free of an active agent which interacts as either agonist or antagonist at any of the SST(1) to SST(5) receptors (particularly in humans).

The term “pre-formulation” herein is a pharmaceutical composition, preferably is a parenteral pharmaceutical composition, more preferably is an injectable parenteral pharmaceutical composition, even more preferably is an injectable parenteral pharmaceutical composition for subcutaneous or intra-muscular application, even more preferably is an injectable parenteral pharmaceutical composition for subcutaneous application.

Optional Additional Components

In one particularly preferred embodiment of the present invention, the compositions (pre-formulations and resulting depots) do not include fragmentation agents, such as polyethyleneoxide or poly(ethylene glycol) (PEG) fragmentation agent, e.g. a PEG grafted lipid and/or surfactant.

For example, the compositions preferably do not include fragmentation agents such as Polysorbate 80 (P80), or other Polysorbates (e.g. Polysorbate 20), PEGylated phospholipids (PEG-lipids such as DSPE-PEG(2000), DSPE-PEG(5000), DOPE-PEG(2000) and DOPE-PEG(5000)), Solutol HS 15, PEGylated fatty acids (e.g. PEG-oleate), block co-polymers such as Pluronic® F127 and Pluronic® F68, ethoxylated castor oil derivatives (e.g. Chremophores), PEGylated glyceryl fatty acid esters (such as TMGO-15 from Nikko Chemicals) and PEGylated tocopherols (such as d-alpha tocopheryl poly(ethylene glycol) 1000 succinate known as Vitamin E TPGS from Eastman.

However, the active agent as a powder (e.g. in the kit of the invention), as well as active agent dissolved in the lipid formulation, may gain stability (both storage and in vivo stability) by certain stabilising additives. Such additives include sugars (e.g. sucrose, trehalose, lactose etc.), polymers (e.g. polyols such as carboxy methyl cellulose), amino acids (such as methionine, glutamate, lysine etc.), lipid-soluble acid components such as HCl, anionic lipids and/or surface active agents (such as dioleoyl phosphatidyl glycerol (DOPG), palmitoyloleoyl phosphatidylglycerol (POPG) and oleic acid (OA)).

Single-dose formats must remain stable and potent in storage prior to use, but are disposable after the single use. It is a remarkable finding that non-aqueous pre-formulations comprising an alkylammonium EDTA salt have enhanced storage stability at elevated temperatures, such as at 25° C. or even 40° C. This offers advantages in terms of ease of transportation and storage (no need for refrigeration). It is preferred that a single dose format has a stability such that after storage for 2 months at 25° C. (with air in head space), the assayed active agent concentration is at least 95% that of the initial assayed active agent concentration, and after 3 months, the assayed active agent concentration is at least 90% that of the initial assayed active agent concentration.

In one preferred embodiment, the pre-formulations, devices and/or kits of the present invention will be stored at above 10° C. (e.g. at 15 to 40° C.), preferably above 20° C., such as at ambient temperature. In a corresponding embodiment, the pre-formulations, devices and/or kits of the present invention will not be stored at refrigeration temperatures (e.g. below 10° C. or below 5° C.) such as 1 to 6° C.

It is preferred that a single dose format has a stability such that after storage for 2 months at 40° C. (with air in head space), the assayed active agent concentration is at least 85% that of the initial assayed active agent concentration, and after 3 months, the assayed active agent concentration is at least 80% that of the initial assayed active agent concentration.

Multi-dose formats must not only remain stable and potent in storage prior to use, but must also remain stable, potent and relatively/effectively free of bacteria over the multiple-dose use regimen administration period after the first use in which a seal has been compromised. For this reason multi-dose formats often require an anti-microbial or microbial-static agent, e.g. bacteriostatic agent, preservative.

However, the production of preserved pharmaceutical preparations containing protein or peptide actives has often proven difficult, as when preservatives are used, these give rise to stability problems. Often the proteins are inactivated and aggregates are formed, which may sometimes lead to reported injection site intolerance or immunogenicity to the active. This can be further aggravated by additional excipients or formulation components.

In one aspect each of the embodiments herein can optionally contain an antimicrobial or microbial-static agent, which includes bacteriostatic agents and preservative. Such agents include benzalkonium chloride, m-cresol, benzyl alcohol or other phenolic preservatives. Typical concentrations as known in the art can be used.

Additional components above those mentioned as components i) (including components a) and c), components b) and d) being optional) and ii) will, where present at all, preferably be present in an amount of 0 to 5% (e.g. 0.01% to 5%) by weight, preferably no more than 2% by weight and more preferably no more than 1% by weight.

In one embodiment, components a) and b) (allowing for any impurity inherent in the nature of these components) make up at least 95% of the lipid components of the pre-formulations. Preferably at least 99% of the total lipid content of the pre-formulation consists of components a) and b). Preferably the lipid component of the pre-formulation consists essentially of components a) and b).

Administration

The pre-formulations of the present invention are generally formulated to be administered parenterally. This administration will generally not be an intra-vascular method but will preferably be subcutaneous (s.c.), intracavitary or intramuscular (i.m.). Typically the administration will be by injection, which term is used herein to indicate any method in which the formulation is passed through the skin, such as by needle, catheter or needle-less (needle-free) injector. It is, however, possible to take advantage of the high loading and other beneficial characteristics of the present formulation in non-parenteral applications, including topical or systemic application to skin, mucous membranes, nasal, buccal and/or oral cavities. Preferably, such non-parenteral administration is for topical use.

Preferred parenteral administration is by i.m or s.c. injection, most preferably by deep s.c. injection. An important feature of the composition of the invention is that it can be administered both by i.m. and s.c. and other routes without toxicity or significant local effects. It is also suitable for intracavital administration. The deep s.c. injection has the advantage of being less deep and less painful to the subject than the (deep) i.m. injection used for some current depots and is technically most suitable in the present case as it combines ease of injection with low risk of local side effects. It is a surprising observation of the present inventors that the formulations provide sustained release of active agent over a predictable time period by both subcutaneous and intramuscular injection. This therefore allows the site of injection to be varied widely and allows the dose to be administered without detailed consideration of the tissue depth at the site of injection.

In one embodiment the lipid pre-formulations of the present invention provide non-lamellar liquid crystalline depot compositions upon exposure to aqueous fluids, especially in vivo. As used herein, the term “non-lamellar” is used to indicate a normal or reversed liquid crystalline phase (such as a cubic or hexagonal phase) or the L3 phase or any combination thereof. The term liquid crystalline indicates all hexagonal, all cubic liquid crystalline phases and/or all mixtures thereof. Hexagonal as used herein indicates “normal” or “reversed” hexagonal (preferably reversed) and “cubic” indicates any cubic liquid crystalline phase unless specified otherwise. The skilled reader will have no difficulty in identifying those compositions having appropriate phase behaviour by reference to the description and Examples provided herein, and to WO2005/117830, but the most favoured compositional area for phase behaviour is where ratio of components a:b are in the region of 40:60 to 70:30, preferably 45:55 to 55:45 and more preferably 40:60 to 54:46. Ratios of around 50:50 (e.g. 49:51 to 51:49) are highly preferred, most preferably around 50:50.

It is important to appreciate that the pre-formulations of the present invention are of low viscosity. As a result, these pre-formulations must not be in any bulk liquid crystalline phase since all liquid crystalline phases have a viscosity significantly higher than could be administered by syringe or similar injecting dispenser. The pre-formulations of the present invention will thus be in a non-liquid crystalline state, such as a solution, L₂ or L₃ phase, particularly solution or L₂. The L₂ phase as used herein throughout is preferably a “swollen” L₂ phase containing greater than 5 wt %, preferably greater than 7%, and most preferably greater than 9% of organic mono-alcoholic solvent (component c) having a viscosity reducing effect.

The pre-formulations described herein are preferably of “low viscosity”. This may be indicated, for example by the ability to be dispensed from a 1 ml disposable syringe through a small gauge needle. Preferably, the low viscosity mixtures can be dispensed through a needle of 19 awg, preferably smaller than 19 gauge, more preferably 23 awg (or most preferably even 27 gauge) needle by manual pressure. In a particularly preferred embodiment, the low viscosity mixture should be a mixture capable of passing through a standard sterile filtration membrane such as a 0.22 μm syringe filter. A typical range of suitable viscosities for the pre-formulations of the invention would be, for example, 1 to 1000 mPas, preferably 10 to 800 mPas, more preferably 50 to 750 mPas and most preferably 50 to 600 mPas at 20° C.

Upon administration, many of the preferred lipid-based pre-formulations of the present invention undergo a phase structure transition from a low viscosity mixture to a high viscosity (generally tissue adherent) depot composition. Generally this will be a transition from a molecular mixture, swollen L₂ and/or L₃ phase to one or more (high viscosity) liquid crystalline phases such as normal or reversed hexagonal or cubic liquid crystalline phases or mixtures thereof. Further phase transitions may also take place following administration. Obviously, complete phase transition is not necessary for the functioning of the invention but at least a surface layer of the administered mixture will form a liquid crystalline structure. Generally this transition will be rapid for at least the surface region of the administered formulation (that part in direct contact with air, body surfaces and/or body fluids). This will most preferably be over a few seconds or minutes (e.g. from 1 second up to 30 minutes, preferably up to 10 minutes, more preferably 5 minutes of less). The remainder of the composition may change phase to a liquid crystalline phase more slowly by diffusion and/or as the surface region disperses.

The invention is not limited to formulations which undergo a phase change to a liquid crystalline structure upon administration. A depot composition may be formed upon administration by other mechanisms not requiring the formation of a liquid crystalline phase. For instance, in the system described in WO2016/066655 the formation of a depot composition is not accompanied by a conversion to a liquid crystalline phase.

Without being bound by theory, it is believed that upon exposure to excess aqueous fluid, the pre-formulations of the invention lose some or all of the organic solvent included therein (e.g. by diffusion) and take in aqueous fluid from the bodily environment (e.g. the in vivo environment). For certain lipid pre-formulations as described herein, at least a part of the formulation preferably generates a non-lamellar, particularly liquid crystalline phase structure. In most cases these non-lamellar structures are highly viscous and are not easily dissolved or dispersed into the in vivo environment. The result is a monolithic “depot” generated in vivo with only a limited area of exposure to body fluids. Furthermore, because the non-lamellar structure has large polar, apolar and boundary regions, the lipid depot is highly effective in solubilising and stabilising active agents such as peptides and protecting these from degradation mechanisms. As the depot composition formed from the pre-formulation gradually degrades over a period of days, weeks or months, the active agent is gradually released and/or diffuses out from the composition. Since the environment within the depot composition is relatively protected, the pre-formulations of the invention are highly suitable for active agents with a relatively low biological half-life (see above).

By incorporation of a co-solvent into the pre-formulations, as described for the first time in WO2012/160213, it is believed that the rate of phase transition to a non-lamellar (e.g. liquid crystalline) phase at the surface of the injected pre-formulation can be enhanced in comparison with compositions containing organic solvents in the substantial absence of water. The performance of the resulting depot is thus improved and further control over the release of active agent achieved.

The depot systems formed by the formulations of the present invention are highly effective in protecting the active agent from degradation and thus allow an extended release period. The formulations of the invention thus may provide in vivo depots of peptide active agents which require administration only once every 5 to 90 days preferably 5 to 60 days, more preferably 6 to 32. Evidently, a longer stable release period is desirable for patient comfort and compliance, as well as demanding less time from health professionals if the composition is not to be self-administered. Where the composition is to be self-administered, patient compliance may be aided by a weekly (e.g. every 7 days, optionally ±1 day), bi-weekly (e.g. every 14 days, optionally ±2 days), or monthly (e.g. every 28 or 30 days (optionally ±7 days) administration so that the need to administer is not forgotten.

A considerable advantage of the depot precursors of the present invention is that they are stable homogeneous phases. That is to say, they may be stored for considerable periods (preferably at least 6 months) at room or refrigerator temperature, without phase separation. As well as providing advantageous storage and facile administration, this allows for the dose of active agent (e.g. Somatostatin analogue, e.g. octreotide) to be selected by reference to the species, age, sex, weight, and/or physical condition of the individual subject, by means of injecting a selected volume.

The present invention thus provides for methods comprising the selection of a dosing amount specific to an individual, particularly by subject weight. The means for this dose selection is the choice of administration volume.

In one preferred aspect, the present invention provides a pre-formulation comprising a lipid mixture i) comprising components a), b), c), and optionally d), component ii), and 0-1.0% water. The amounts of these components will typically be in the range 20-60% a), 20-60% b), 1-30% c) and 0.001-0.8% ii).

The pre-formulations of the present invention are highly advantageous in that they are stable to prolonged storage in their final “administration ready” form. As a result, they may readily be supplied for administration either by health professionals or by patients or their carers, who need not be fully trained health professionals and may not have the experience or skills to make up complex preparations. This is particularly important in long-duration, slow-effecting diseases such as diabetes.

Devices

In a yet further aspect, the present invention provides a disposable administration device (which is also to include a device component) pre-loaded with a measured dose of a pre-formulation of the present invention. Such a device will typically contain a single dose ready for administration, and will generally be sterile-packed such that the composition is stored within the device until administration. Suitable devices include cartridges, ampoules and particularly syringes and syringe barrels, either with integral needles or with standard (e.g. luer) fittings adapted to take a suitable disposable needle.

Kits

The pre-filled devices of the invention may also suitably be included in an administration kit, which kit also forms a further aspect of the invention. In a still further aspect, the invention thus provides a kit for the administration of at least one active agent, said kit containing a measured dose of a formulation of the invention and optionally an administration device or component thereof. Preferably the dose will be held within the device or component, which will be suitable for i.m. or preferably s.c. administration. The kits may include additional administration components such as needles, swabs, etc. and will optionally and preferably contain instructions for administration. Such instructions will typically relate to administration by a route as described herein and/or for the treatment of a disease indicated herein above.

The invention provides for a pre-filled administration device as indicated herein and a kit as indicated herein comprising a pre-formulation as described herein.

In an alternative aspect of the present invention, the “kit” may contain at least two vessels, a first containing a low viscosity mixture of i) a lipid mixture comprising components a), c) and optionally b), and ii), as described here, and a second containing a measured dose of at least one active agent d) as described herein.

Such a “two component kit” may comprise the active agent d) as a powder formulation in one vial or pre-filled syringe and components i) and ii) in a second vial or pre-filled syringe. In the case of two syringes, before injection, the pre-filled syringes are connected and the powder comprising active agent is mixed with the matrix formulation by moving the syringe barrels back and forth, forming a solution or suspension which is injected. Alternatively, the liquid lipid formulation is drawn from one vial, or is pre-filled into a syringe, and is injected into a vial containing powdered active agent (e.g. peptide). This formulation may subsequently be mixed by hand shaking or other suitable reconstitution method (e.g. vortex mixing etc.). The solvent component may be present in either or both vessels (e.g. vials or syringes). Where the solvent is at least partially constituted with the active agent, this will generally be in the form of a solution or suspension.

In this aspect, the invention therefore provides a two component kit comprising

1) a first vessel containing a low viscosity mixture of components a) to c) as described herein; 2) an optional second vessel containing at least one peptide active agent, 3) an antioxidant component ii) optionally in a third vessel, preferably in the second vessel, or most preferably in the first vessel; 4) optionally and preferably at least one of:

-   -   5) at least one syringe (which may be one or both of said first         and second vessels);     -   6) a needle for administration, such as those described herein;     -   7) instructions for generation of a composition of the invention         from the contents of the first and second vessels;     -   8) instructions for administration, whereby to form a depot as         described herein.

Preferred Features and Combinations

In combination with the features and preferred features indicated herein, the mixtures, e.g. pre-formulations, of the invention may have one or more of the following preferred features independently or in combination:

All proportions indicated herein may optionally be varied by up to 10% of the amount specified, optionally and preferably by up to 5%;

Component a) comprises, consists essentially of or preferably consists of GDO; Component b) comprises, consists essentially of or preferably consists of soy PC; Component c) comprises, consists essentially of or preferably consists of a 1, 2, 3 or 4 carbon alcohol, preferably isopropanol or more preferably ethanol;

Component c) includes a polar co-solvent such as propylene glycol;

The pre-formulation does not contain any somatostatin analogue (as described herein);

The pre-formulation has a low viscosity as indicated herein; The pre-formulation forms a non-lamellar liquid crystalline phase as indicated herein upon in vivo administration;

The pre-formulation generates a depot following in vivo administration, which depot releases at least one active agent at a therapeutic level over a period of at least 7 days, preferably at least 21 days, more preferably at least 28 days;

In combination with the features and preferred features indicated herein, the method(s) of treatment of the present invention may have one or more of the following preferred features independently or in combination;

The method comprises the administration of at least one formulation with one or more preferred features as indicated above;

The method comprises the administration of at least one formulation as indicated herein by i.m., s.c. (e.g. deep s.c.) injection;

The method comprises administration by means of a pre-filled administration device as indicated herein;

The method comprises administration through a needle no larger than 20 gauge, preferably smaller than 20 gauge, and most preferably 22 gauge, 23 gauge or smaller;

The method comprises a single administration every 5 to 90 days, preferably 6 to 32 days (for example 7 days or 28-31 days);

In combination with the features and preferred features indicated herein, the use(s) of the pre-formulations indicated herein in the manufacture of medicaments may have one or more of the following preferred features independently or in combination;

The use comprises the use of at least one formulation with one or more preferred features as indicated above;

The use comprises the manufacture of a medicament for administration of at least one formulation as indicated herein by i.m. or s.c. injection;

The use comprises the manufacture of a medicament for administration by means of a pre-filled administration device as indicated herein;

The use comprises the manufacture of a medicament for administration through a needle no larger than 20 gauge, preferably smaller than 20 gauge, and most preferably 22 gauge, 23 gauge or smaller;

The use comprises the manufacture of a medicament for administration once every 5 to 90 days, preferably 5 to 60 days, more preferably 6 to 32 days;

In combination with the features and preferred features indicated herein, the pre-filled devices of the invention may have one or more of the following preferred features independently or in combination:

They contain a preferred formulation as indicated herein;

They comprise a needle smaller than 20 gauge, preferably no larger than 22 gauge or no larger than 23 gauge;

They contain a homogeneous mixture of a composition of the invention in ready-to-inject form.

They contain a formulation of components i) (preferably comprising a), b) and c)) and ii) for combination with an active agent.

They contain a total volume for administration of no more than 5 ml, preferably no more than 3 ml more preferably no more than 1.5 ml.

In combination with the features and preferred features indicated herein, the kits of the invention may have one or more of the following preferred features independently or in combination:

They contain a preferred formulation as indicated herein; They contain a pre-filled device as indicated herein; They contain a needle smaller than 20 gauge, preferably no larger than 22 gauge or no larger than 23 gauge;

They contain peptide active agent;

They contain a total volume for administration of no more than 5 ml, preferably no more than 3 ml more preferably no more than 1.5 ml;

They contain instructions for administration by a route and/or at a frequency as indicated herein;

They contain instructions for administration for use in a method of treatment as described herein;

The Invention will now be further illustrated by reference to the following non-limiting Examples and the attached Figures.

EXAMPLES

Materials

All materials used in the Examples were obtained from commercial sources and were of pharmacopoeial grade where applicable or of the highest purity grade available. The following abbreviations are used throughout the Examples:

API Active pharmaceutical ingredient

DiETA Diethanolamine

DTPA Diethylenetriaminepentaacetic (pentetic) acid EtOH Ethanol (99.7% Ph. Eur) EDTA Ethylenediaminetetraacetic (edetic) acid (USP/NF) EDTA(Na) Ethylenediaminetetraacetic acid disodium dihydrate

ETA Ethanolamine (USP/NF)

FeCl₃×6H₂O Iron(III) chloride hexahydrate GDO Glycerol dioleate (Cithrol GDO HP-SO-(LK) from Croda) GMO Glycerol monooleate GOS(Ac) Goserelin acetate GOS(C1) Goserelin chloride GRN(0) Granisetron free base OCT(C1) Octreotide hydrochloride OXY(Ac) Oxytocin acetate OXY(C1) Oxytocin chloride PG Propylene glycol (Ph. Eur)

SbOil Soybean oil

SOM(Ac) Somatostatin-14 acetate SOM(C1) Somatostatin-14 chloride SPC Soy phosphatidylcho line (Lipoid S100 from Lipoid)

TRIS Tris(hydroxymethyl)aminomethane

General Procedures

Preparation of EDTA and EDTA(Na) Solutions in EtOH/PG

Samples were prepared by weighing the appropriate amounts of EDTA or EDTA(Na) and alkylamine into glass vials, e.g. 15R vials, followed by addition of organic solvent or solvent mixture (e.g EtOH/PG (50/50 w/w)). Vials were sealed and placed on either a roller mixer by end-over-end rotation at ambient RT or magnetic stirrer. During dissolution, vials were visually inspected for undissolved EDTA particles using ambient and cross-polarized light.

Preparation of FeCl₃×6H₂O Solutions

Samples were prepared by weighing the appropriate amount of FeCl₃×6H₂O into sterilized glass vials followed by addition of organic solvent or solvent mixture. Vials were sealed and placed on a roller mixer by end-over-end rotation at ambient RT until FeCl₃×6H₂O was completely dissolved.

Preparation of SOM(C1)

For the ion-exchange process, approximately 120 g of Dowex 1×2 chloride form (50-100 mesh) resin was mixed with an equal amount of Millipore water, added to a 200 mL glass ion-exchange column and left to equilibrate overnight. Next day, prior to ion-exchange the Dowex matrix was slowly washed with 900 ml Millipore water and the ion-exchange process was initiated. 3.743 g of SOM(Ac) was dissolved in 112.4 g Millipore water. Freshly prepared (within approx. 30 min) SOM(Ac) solution was loaded onto the top of the ion-exchange column. The flow (at approx. 15 s/mL) was initiated and eluate fractions of 50-250 mL each were collected by continuously rinsing the column with Millipore water. The eluate fractions with conductivity greater than 50 μS/cm were pooled, transferred into three 1000 mL round-bottom flasks, shell-frozen in EtOH/dry-ice using Rotavapor R-200, placed to cool at −80° C. for about 1 h and lyophilized overnight for about 36 h. The obtained amount and yield of SOM(C1) were 3.096 g and 82.7%, respectively. The complete exchange of acetate to chloride was confirmed by determination of the two anions by indirect HPLC-UV.

Preparation of GOS(C1)

For the ion-exchange process, 34.7995 g of Dowex 1×2 chloride form (50-100 mesh) resin was mixed with 36.6327 g Millipore water, added to a 100 mL glass ion-exchange column and left to equilibrate overnight. Next day, prior to ion-exchange, the Dowex matrix was slowly washed with 700 ml Millipore water and the ion-exchange process was initiated. 0.8353 g of GOS(Ac) was dissolved in 13.9534 g Millipore water. Freshly prepared (within approx. 30 min) GOS(Ac) solution was loaded onto the top of the ion-exchange column. The flow (at approx. 15 s/mL) was initiated and eluate fractions of 15-50 mL each were collected by continuously rinsing the column with Millipore water. The eluate fractions with conductivity greater than 35 μS/cm were pooled, transferred into a 500 mL round-bottom flask, shell-frozen in EtOH/dry-ice using Rotavapor R-200, placed to cool at −80° C. for about 1 h and lyophilized for about 23 h. The obtained amount and yield of GOS(C1) were 0.739 g and 88.5%, respectively. The complete exchange of acetate to chloride was confirmed by determination of the two anions by indirect HPLC-UV.

Preparation of OXY(C1)

For the ion-exchange process, 31.5493 g of Dowex 1×2 chloride form (50-100 mesh) resin was mixed with 42.1860 g Millipore water, added to a 100 mL glass ion-exchange column and left to equilibrate overnight. Next day, prior to ion-exchange, the Dowex matrix was slowly washed with 600 ml Millipore water and the ion-exchange process was initiated. 0.7933 g of OXY(Ac) was dissolved in 12.5166 g Millipore water. Freshly prepared (within approx. 30 min) OXY(Ac) solution was loaded onto the top of the ion-exchange column. The flow (at approx. 15 s/mL) was initiated and eluate fractions of 15-50 mL each were collected by continuously rinsing the column with Millipore water. The eluate fractions with conductivity greater than 25 μS/cm were pooled, transferred into a 500 mL round-bottom flask, shell-frozen in EtOH/dry-ice using Rotavapor R-200, placed to cool at −80° C. for about 1 h and lyophilized overnight for about 25 h. The obtained amount and yield of OXY(C1) was 0.686 g and 86.5%, respectively. The complete exchange of acetate to chloride was confirmed by determination of the two anions by indirect HPLC-UV.

Preparation of Lipid Formulations

Lipid placebo formulations were prepared by weighing appropriate amounts of SPC, GDO, EDTA/alkylamine solution, and FeCl₃×6H₂O (when needed) solution into sterilized glass vials. The sealed vials were then placed on a roller mixer at room temperature until mixed completely into clear homogeneous liquid solution (<24 hours).

API-containing formulations were prepared by adding appropriate amounts of API powder to the lipid placebo formulations in sterilized glass vials. The vials were sealed and placed on a roller mixer at room temperature until mixed completely into clear homogeneous liquid solution (ca. 24 hours).

As an example, EDTA and ETA (at EDTA:ETA molar ratio 1:4) were dissolved in EtOH/PG (50/50 w/w) mixture. Then, appropriate amounts of SPC, GDO (at SPC/GDO weight ratio 50/50) and EtOH/PG/EDTA/ETA mixture were weighed into a sterilized 20R glass vial. The sealed vial was then placed on a roller mixer at room temperature until mixed completely into clear homogeneous liquid solution (<24 hours). OCT(C1) powder was then added to the lipid formulations in sterilized 15R glass vial at 2.34 wt % concentration. The vial was sealed and placed on a roller mixer at room temperature until mixed completely into clear homogeneous liquid solution (24 hours).

Evaluation of Octreotide Stability in Lipid Formulations (Typical Method)

Prepared lipid peptide (e.g. octreotide) formulations as above were divided into sterilized 2R glass vials (0.5 g of formulation per vial). The head space of the vials was ambient air, i.e., no inert atmosphere such as nitrogen was introduced in the head space. Vials were sealed and placed in controlled environment storage cabinets at 25° C./60% RH and 40° C./75% RH. At predefined sampling points (up to three months of storage) two vials of each formulation and storage cabinet were withdrawn, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

It should be noted that the filling procedure and storage conditions ensured forced degradation conditions as the head space was composed of air rather than inert atmosphere such as nitrogen.

HPLC-UV Determination of Peptides in Lipid Formulations

Determination of peptide (e.g. octreotide, such as octreotide chloride) in lipid formulations was carried out by gradient HPLC with UV detection. The HILIC analytical column used was a HALO Penta-HILIC 2.7 μm, 150×3.0 mm. Quantification was carried out by interpolating the peptide (e.g. octreotide) peak area obtained in lipid formulation samples (prepared by dissolving the lipid formulation in a sample solvent at the required target peptide concentration) into the calibration curves generated from standard solutions containing known concentrations of the corresponding peptide.

A typical mobile phases used (for example with octreotide) consisted of water: 2M sodium chloride:acetonitrile:trifluoroacetic acid 384:16:400:1 (v/v) (mobile phase A) and water:methanol:acetonitrile:trifluoroacetic acid 20:30:950:1 (v/v) (mobile phase B). The detection was carried out at 220 nm. The sample solvent used was acetonitrile:methanol (1:1, v/v); octreotide eluted after approximately 25.2 min.

Data Presentation

In the example section, in addition to absolute API assay values, results are also in some cases expressed as a Stability Index for API assay. The Stability Index is calculated as the API assay value in the particular formulation divided by the API assay value in the reference formulation. Expressed in this way, Stability Index values greater than 1 means improved API stability when compared to the reference formulation.

Measurement of Vial Headspace Oxygen Concentration

Oxygen concentration in the vial headspace was measured using a PC-controlled PreSens Microx TX3 micro fiber optic oxygen transmitter equipped with a needle-type optical oxygen microsensor (NTH, 140 μm flat broken tip). Measurements were performed by penetrating the oxygen microsensor through the vial rubber stopper into the vial headspace and measuring the oxygen concentration until a stable readout was obtained (about 1 min).

Example 1. EDTA Solubility in the Presence and Absence of Alkylamine

0.08 wt % EDTA and EDTA(Na) solutions in EtOH/PG (50/50 w/w) were prepared in the presence and absence of ETA (Table 1). Dissolution of EDTA and EDTA(Na) during end-over-end rotation at ambient RT was assessed by visual inspection (ambient and crossed-polarized light) over 27 days. The results show that neither the disodium salt (EDTA(Na)) nor the acid form of EDTA is soluble in EtOH/PG without using ETA even after 27 days of mixing. The obtained results also show that EDTA(Na) is not soluble in EtOH/PG even in the presence of ETA whereas the acid form of EDTA is solubilized in EtOH/PG in the presence of 4 mol ETA per 1 mol of EDTA already after 24 hours mixing.

TABLE 1 Solubility of 0.08 wt % EDTA and EDTA(Na) in EtOH/PG in the presence and absence of ETA. ETA/EDTA Observations after mixing for Sample No EDTA type (mol/mol) 24 h 27 days Sample 1 Disodium 0.00 Not soluble Not soluble dihydrate Sample 2 Acid form 0.00 Not soluble Not soluble Sample 3 Disodium 3.94 Not soluble Not soluble dihydrate Sample 4 Acid form 3.95 Soluble Soluble

Example 2. EDTA Solubility as a Function of ETA/EDTA Molar Ratio

Table 2 summarizes results on EDTA solubility at a concentration of 0.38 wt % in EtOH/PG solvent mixtures (1/1 wt/wt) as a function of ETA/EDTA molar ratio. The only sample where EDTA was not fully dissolved was for the lowest ETA/EDTA molar ratio. In all other samples EDTA was soluble after 24 h end-over-end rotation mixing at ambient RT. The obtained results show that about 3.5 mol of ETA per 1 mol of EDTA is close to the required minimum amount needed to solubilize EDTA in the non-aqueous solvent used.

TABLE 2 Solubility of 0.38 wt % EDTA in EtOH/PG as a function of ETA/EDTA molar ratio. ETA/EDTA EDTA solubility Sample ID (mol/mol) (ca 24 h mixing) Sample 5 2.83 Not soluble Sample 6 3.49 Soluble Sample 7 3.90 Soluble Sample 8 3.90 Soluble Sample 9 4.02 Soluble Sample 10 3.99 Soluble Sample 11 4.30 Soluble Sample 12 4.24 Soluble Sample 13 4.45 Soluble Sample 14 4.48 Soluble Sample 15 4.62 Soluble Sample 16 4.65 Soluble

Example 3. EDTA Solubility as a Function of DiETA/EDTA Molar Ratio

Table 3 summarizes EDTA solubility results in EtOH/PG (1/1 wt/wt) solvent mixture at 0.38 wt % EDTA as a function of DiETA/EDTA molar ratio after 24 h end-over-end rotation mixing at ambient RT. The obtained results show that about 4.5 mol of DiETA per 1 mol of EDTA is close to the required minimum amount needed to solubilize EDTA in non-aqueous solvent used.

TABLE 3 Solubility of 0.38 wt % EDTA in EtOH/PG as a function of DiETA/EDTA molar ratio. DiETA/EDTA EDTA solubility Sample ID (mol/mol) (ca 24 h mixing) Sample 17 2.14 Not soluble Sample 18 2.68 Not soluble Sample 19 3.20 Not soluble Sample 20 3.52 Almost fully soluble Sample 21 3.97 Soluble or almost fully soluble Sample 22 4.51 Soluble Sample 23 5.09 Soluble

Example 4. EDTA Solubility as a Function of Ethylenediamine/EDTA Molar Ratio

Table 4 summarizes EDTA solubility results in EtOH/PG (1/1 wt/wt) solvent mixture at 0.38 wt % EDTA as a function of ethylenediamine/EDTA molar ratio after 24 h end-over-end rotation mixing at ambient RT. The obtained results showed that about 2.5 mol of ethylenediamine per 1 mol of EDTA is close to the required minimum amount needed to solubilize EDTA in non-aqueous solvent used.

TABLE 4 Solubility of 0.38 wt % EDTA in EtOH/PG as a function of ethylenediamine/EDTA molar ratio. Ethylenediamine/EDTA EDTA solubility Sample ID (mol/mol) (ca 24 h mixing) Sample 24 1.96 Not soluble Sample 25 2.45 Soluble Sample 26 3.09 Soluble Sample 27 3.46 Soluble Sample 28 3.92 Soluble Sample 29 4.47 Soluble Sample 30 5.00 Soluble

Example 5. EDTA Solubility as a Function of Serinol/EDTA Molar Ratio

Table 5 summarizes EDTA solubility results in EtOH/PG (1/1 wt/wt) solvent mixture at 0.38 wt % EDTA as a function of serinol/EDTA molar ratio after 24 h end-over-end rotation mixing at ambient RT. The obtained results showed that about 4 mol of serinol per 1 mol of EDTA is close to the required minimum amount needed to solubilize EDTA in non-aqueous solvent used.

TABLE 5 Solubility of 0.38 wt % EDTA in EtOH/PG as a function of serinol/EDTA molar ratio. Serinol/EDTA EDTA solubility Sample ID (mol/mol) (ca 24 h mixing) Sample 31 1.88 Not soluble Sample 32 2.36 Not soluble Sample 33 3.32 Not soluble Sample 34 3.48 Almost soluble Sample 35 4.11 Soluble Sample 36 4.77 Soluble Sample 37 5.09 Soluble Sample 38 5.45 Soluble

Example 6. EDTa Solubility as a Function of TRIS/EDTA Molar Ratio

Table 6 summarizes EDTA solubility results in EtOH/PG (1/1 wt/wt) solvent mixture at 0.38 wt % EDTA as a function of TRIS/EDTA molar ratio after 7 days end-over-end rotation mixing at ambient RT. The obtained results showed that about 5 mol of TRIS per 1 mol of EDTA is close to the required minimum amount needed to solubilize EDTA in non-aqueous solvent used.

TABLE 6 Solubility of 0.38 wt % EDTA in EtOH/PG as a function of TRIS/EDTA molar ratio. TRIS/EDTA EDTA solubility Sample ID (mol/mol) (ca 7 days mixing) Sample 39 2.03 Not soluble Sample 40 2.57 Not soluble Sample 41 2.96 Not soluble Sample 42 3.52 Not soluble Sample 43 3.97 Almost soluble Sample 44 4.49 Almost soluble Sample 45 5.04 Soluble Sample 46 4.98 Soluble Sample 47 5.55 Soluble Sample 48 5.98 Soluble Sample 49 6.48 Soluble Sample 50 6.97 Soluble Sample 51 7.47 Soluble Sample 52 8.03 Soluble

Example 7. Stability of OCT(C1) in Lipid Formulations in the Presence of EDTA

Lipid formulations containing 2.34 wt % of OCT(C1) in the presence and absence of 100 ppm of EDTA were prepared according to the compositions given in Table 7. Formulations were divided into sterilized 2R glass vials (0.5 g of formulation per vial), sealed and placed in controlled environment storage cabinets at either 40° C./75% RH or 25° C./60% RH. The headspace of the vials was ambient air to ensure forced degradation conditions, i.e., no inert atmosphere such as nitrogen was introduced. At predefined sampling points (up to three months of storage), two vials of each formulation and storage condition were withdrawn from the controlled environment cabinets, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 7 OCT(Cl) containing FluidCrystal ® formulation compositions (in wt %) with and without EDTA. Sample ID OCT(Cl) SPC GDO EtOH PG ETA EDTA Sample 53 2.34 42.33 42.33 6.50 6.50 — — Sample 54 2.34 42.32 42.32 6.50 6.50 0.01 0.01

Samples of the two formulations were placed on stability as described under General Procedures. It should be noted that the filling procedure and storage conditions ensured forced degradation conditions as the head space was composed of air rather than inert atmosphere such as nitrogen. FIG. 1 presents the octreotide assay at different storage time points and storage conditions. As shown in FIG. 1, the presence of 0.01 wt % (100 ppm) of EDTA solubilized in the lipid formulation by the use of 0.01 wt % (100 ppm) ETA dramatically enhanced the peptide stability at both storage conditions.

Example 8. Effect of EDTA Concentration on Peptide Stability

Lipid formulations containing 2.27 wt % of OCT(C1) and different concentrations of EDTA were prepared according to the compositions given in Table 8. Formulations were divided into sterilized 2R glass vials (0.5 g of formulation per vial), sealed and placed in controlled environment storage cabinets at either 40° C./75% RH or 25° C./60% RH. The head space of the vials was ambient air to ensure forced degradation conditions, i.e., no inert atmosphere such as nitrogen was introduced. At predefined sampling points (up to six months of storage) two vials of each formulation and storage condition were withdrawn from the controlled environment cabinets, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 8 Formulation compositions with different concentrations of EDTA (all components in wt %) comprising 2.27 wt % OCT(Cl). Sample ID OCT(Cl) SPC GDO EtOH PG ETA EDTA Sample 55 2.27 42.37 42.37 6.50 6.50 — — Sample 56 2.27 42.36 42.36 6.50 6.50 0.004 0.005 Sample 57 2.27 42.36 42.36 6.50 6.50 0.008 0.010 Sample 58 2.27 42.34 42.34 6.50 6.50 0.021 0.025 Sample 59 2.27 42.32 42.32 6.50 6.50 0.042 0.050 Sample 60 2.27 42.30 42.30 6.50 6.50 0.063 0.075

Samples of the six formulations were placed on stability as described under General Procedures. It should be noted that the filling procedure and storage conditions ensured forced degradation conditions as the head space was composed of air rather than inert atmosphere such as nitrogen. The results are shown in FIG. 2. As shown, the presence of EDTA solubilized in the lipid formulation with the help of ETA dramatically enhanced the peptide stability vs. the reference formulation not containing EDTA/ETA. The maximum stabilization effect was achieved within the concentration interval 50-250 ppm (0.005-0.025 wt %) EDTA.

Example 9. Long-Term Stability of OCT(C1) in Lipid Formulations in the Presence of EDTA

Lipid formulations containing OCT(C1) in the absence and presence of 100 ppm EDTA were prepared according to the compositions given in Table 9. Formulations were divided into sterilized 1 mL 22Gx1/2″ glass syringes (Schott AG) (0.5 g of formulation per syringe), sealed with plunger and placed in a controlled environment storage cabinet at 25° C./60% RH. At predefined sampling points (up to twelve months of storage), two syringes of each formulation were withdrawn from the controlled environment cabinet, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 9 OCT(Cl) containing lipid formulation compositions (in wt %) without and with EDTA. The octreotide content corresponds to 20 mg/mL octreotide free base when corrected for peptide content, purity and formulation density. Sample ID OCT(Cl) SPC GDO EtOH PG ETA EDTA Sample 61 2.27 42.37 42.37 6.50 6.50 — — Sample 62 2.27 42.36 42.36 6.50 6.50 0.008 0.010

FIG. 3 presents the octreotide assay at different storage time points. As shown, the presence of 0.01 wt % (100 ppm) of EDTA solubilized in the lipid formulation with the help of ETA significantly enhanced the long-term peptide stability in pre-filled syringes at the long-term 25° C./60% RH storage condition.

Example 10. Stability of OCT(C1) in Lipid Formulations in the Presence of Iron and EDTA

Lipid formulations containing OCT(C1) and different amounts of Fe³⁺ and EDTA were prepared according to the compositions given in Table 10. Formulations were divided into sterilized 2R glass vials (0.5 g of formulation per vial), sealed and placed in a controlled environment storage cabinet at 40° C./75% RH. The head space of the vials was ambient air to ensure forced degradation conditions, i.e., no inert atmosphere such as nitrogen was introduced. At 1-month sampling point two vials of each formulation and storage condition were withdrawn from the controlled environment cabinet, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 10 OCT(Cl) containing FluidCrystal ® formulation compositions (in wt %) with different concentrations of Fe³⁺ and EDTA. The octreotide content corresponds to 20 mg/mL octreotide free base when corrected for peptide content, purity and formulation density. The SPC/GDO weight ratio is 50/50 in all formulations. Sample ID OCT(Cl) SPC + GDO EtOH PG EDTA ETA FeCl₃ × 6H₂O* Sample 63 2.27 84.73000 6.50 6.50 — — — Sample 64 2.27 84.72903 6.50 6.50 — — 0.00097 Sample 65 2.27 84.72758 6.50 6.50 — — 0.00242 Sample 66 2.27 84.72516 6.50 6.50 — — 0.00484 Sample 67 2.27 84.72541 6.50 6.50 0.00250 0.00209 — Sample 68 2.27 84.72444 6.50 6.50 0.00250 0.00209 0.00097 Sample 69 2.27 84.72299 6.50 6.50 0.00250 0.00209 0.00242 Sample 70 2.27 84.72057 6.50 6.50 0.00250 0.00209 0.00484 Sample 71 2.27 84.71164 6.50 6.50 0.01000 0.00836 — Sample 72 2.27 84.71067 6.50 6.50 0.01000 0.00836 0.00097 Sample 73 2.27 84.70922 6.50 6.50 0.01000 0.00836 0.00242 Sample 74 2.27 84.70680 6.50 6.50 0.01000 0.00836 0.00484 Sample 75 2.27 84.68409 6.50 6.50 0.02500 0.02091 — Sample 76 2.27 84.68312 6.50 6.50 0.02500 0.02091 0.00097 Sample 77 2.27 84.68167 6.50 6.50 0.02500 0.02091 0.00242 Sample 78 2.27 84.67925 6.50 6.50 0.02500 0.02091 0.00484 *0.00097, 0.00242, and 0.00484 wt % of FeCl₃ × 6H₂O corresponds to 2, 5, and 10 ppm of Fe³⁺, respectively.

FIG. 4 presents the octreotide assay at 1-month time point as a function of Fe³⁺ concentration in the presence of different amounts of EDTA. As evident, with increasing the Fe³⁺ concentration, more EDTA is needed to protect OCT from degradation. The protection against OCT degradation in the presence of Fe³⁺ is enhanced with increasing EDTA concentration up to 100 ppm, followed by some decline between 100 and 250 ppm. There is also a clear correlation between Fe³⁺ concentration and amount of EDTA needed to suppress the catalytic activity of iron. As shown in FIG. 5, a maximum stabilization effect is achieved starting from EDTA:Fe³⁺ molar ratio of about 2:1. This corresponds to about 100 ppm EDTA at a Fe³⁺ content of 10 ppm.

Example 11. Stability of OCT(C1) in Lipid Formulations with EDTA and Iron in the Absence and Presence of ETA

Lipid formulations containing EDTA or EDTA(Na) in the absence and presence of ETA were prepared according to the compositions given in Table 11. As shown in Example 1, neither EDTA(Na) nor EDTA are soluble in EtOH/PG without using ETA. EDTA(Na) was also insoluble in EtOH/PG even in the presence of ETA as assessed by visual inspection. Therefore, EDTA(Na), EDTA and EDTA(Na)/ETA containing mixtures in EtOH/PG were additionally filtered using a Millex-LG hydrophilic PTFE 0.2 μm syringe filter to remove the non-dissolved EDTA particles. After preparation, formulations were divided into sterilized 2R glass vials (0.5 g of formulation per vial), sealed and placed in a controlled environment storage cabinet at 40° C./75% RH. The headspace of the vials was ambient air to ensure forced degradation conditions, i.e., no inert atmosphere such as nitrogen was introduced. At predefined sampling points (up to two months of storage) two vials of each formulation and storage condition were withdrawn from controlled environment cabinets, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 11 OCT(CI) containing lipid formulation compositions (in wt %) with different concentrations of Fe³⁺ and EDTA. The octreotide content corresponds to 20 mg/mL octreotide free base when corrected for peptide content, purity and formulation density. The SPC/GDO weight ratio was 50/50 in all formulations. Sample ID OCT (Cl) SPC + GDO EtOH PG EDTA EDTA(Na) ETA FeCl₃ × 6H₂O** Sample 79 2.27 84.73 6.50 6.50 — — — — Sample 80* 2.27 84.72 6.50 6.50 — 0.01 — 0.00242 Sample 81* 2.27 84.71 6.50 6.50 — 0.01 0.00840 0.00242 Sample 82* 2.27 84.72 6.50 6.50 0.01 — — 0.00242 Sample 83 2.27 84.71 6.50 6.50 0.01 — 0.00840 0.00242 *For preparation of these formulations, EDTA mixtures in EtOH/PG were filtered using Millex-LG hydrophilic PTFE 0.2 μm syringe filter to remove insoluble EDTA particles. **0.00242 wt % of FeCl₃ × 6H₂O corresponds to 5 ppm of Fe³⁺.

FIG. 6 presents the assay and Stability Index values of octreotide as a function of time, respectively. As seen, only EDTA solubilized in the lipid formulation with the help of ETA dramatically enhanced the peptide stability compared to the reference formulation in the presence of 5 ppm Fe³⁺. Under the same conditions, formulations containing EDTA(Na), EDTA or EDTA(Na)/ETA showed negative effect on OCT(C1) stability (vs. the reference formulation).

Example 12. Effect of Different Alkylamines and Solvents on Stability of OCT(C1) in Lipid Formulations with EDTA

Lipid formulations were prepared according to the compositions given in Table 12. Formulations were divided into sterilized 2R glass vials (0.5 g of formulation per vial), sealed and placed in a controlled environment storage cabinet at 40° C./75% RH. The headspace of the vials was ambient air to ensure forced degradation conditions, i.e., no inert atmosphere such as nitrogen was introduced. At predefined sampling points (up to two months of storage) two vials of each formulation and storage condition were withdrawn from the controlled environment cabinets, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 12 OCT(Cl) containing lipid formulation compositions (in wt %). The octreotide content corresponds to 20 mg/mL octreotide free base when corrected for peptide content, purity and formulation density. The SPC/GDO weight ratio was 50/50 and ETA:EDTA, DiETA:EDTA, and ethylenediamine:EDTA molar ratios were 4:1 in all formulations. Sample ID OCT (Cl) SPC + GDO EtOH PG EDTA ETA DiETA Ethylene diamine Sample 84 2.27 84.71160 6.50 6.50 0.01 0.0084 — — Sample 85 2.27 84.70560 6.50 6.50 0.01 — 0.01440 — Sample 86 2.27 84.71180 6.50 6.50 0.01 — — 0.00820

FIG. 7 presents the octreotide assay at different storage time points. As shown, the different alkylamines (ETA, DiETA or ethylenediamine) used to solubilize 0.01 wt % (100 ppm) of EDTA into the lipid formulations enhanced the peptide stability to a similar high degree when compared to the reference formulation. The obtained results also show that the positive effect of EDTA on the stability of OCT(CI) is independent on the mixture used to prepare the lipid formulations as indicated by the data for EtOH/PG containing formulations in FIG. 8 when compared with FIG. 9.

Example 13. Stability of SOM(C1) in Lipid Formulations in the Presence of EDTA

Lipid formulations containing SOM(C1) in the absence and presence of 100 ppm EDTA using EtOH/PG, were prepared according to the compositions given in Table 13. Formulations were divided into sterilized 2R glass vials (0.5 g of formulation per vial), sealed and placed in controlled environment storage cabinets at either 40° C./75% RH or 25° C./60% RH. The head space of the vials was ambient air to ensure forced degradation conditions, i.e., no inert atmosphere such as nitrogen was introduced. At predefined sampling points (up to three months of storage) two vials of each formulation and storage condition were withdrawn from the controlled environment cabinets, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 13 SOM(Cl) containing lipid formulation compositions (in wt %) without and with EDTA. The SPC/GDO weight ratio was 50/50 in all formulations. Sample ID SOM(Cl) SPC + GDO EtOH PG EDTA ETA Sample 89 2.00 86.00000 10.00 2.00 — — Sample 90 2.00 85.98164 10.00 2.00 0.01000 0.00836

FIG. 9 presents the SOM assay at different storage time points and storage conditions. As shown, the presence of 100 ppm of EDTA solubilized in the lipid formulation by the use of ETA dramatically enhanced the peptide stability at both 40° C./75% RH and 25° C./60% RH storage conditions.

Example 14. Stability of GOS(C1) in Lipid Formulations in the Presence of EDTA and Iron

Lipid formulations containing GOS(C1) in the absence and presence of 100 ppm EDTA were prepared according to the compositions given in Table 14. Formulations were divided into sterilized 2R glass vials (0.9 g of formulation per vial), sealed and placed in a controlled environment storage cabinet at 40° C./75% RH. The headspace of the vials was ambient air to ensure forced degradation conditions, i.e., no inert atmosphere such as nitrogen was introduced. Both formulations also contained 5 ppm Fe³⁺ to ensure additional oxidative stress conditions. At predefined sampling points (up to two months of storage) two vials of each formulation were withdrawn from controlled environment cabinets, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 14 GOS(Cl) containing lipid formulation compositions (in wt %) without and with EDTA. The SPC/GDO weight ratio is 50/50 in all formulations. Sample ID GOS(Cl) SPC + GDO EtOH DMSO EDTA ETA FeCl₃ × 6H₂O* Sample 93 1.00 78.99758 10.00 10.00 — — 0.00242 Sample 94 1.00 78.97918 10.00 10.00 0.01 0.0084 0.00242 *0.00242 wt % of FeCl₃ × 6H₂O corresponds to 5 ppm of Fe³⁺

FIG. 10 presents the assay and Stability Index values of GOS as a function of time, respectively. As evident, the use of 100 ppm EDTA solubilized in the lipid formulation with the help of ETA significantly enhanced the peptide stability in the presence of 5 ppm Fe³⁺. The data indicate that EDTA provides protection of the peptide towards low to moderate levels of metals that may originate from the excipients, the API or the processing equipment.

Example 15. Stability of OXY(C1) in Lipid Formulations in the Presence of EDTA and Iron

Lipid formulations containing OXY(CI) in the absence and presence of 100 ppm EDTA were prepared according to the compositions given in Table 15. Formulations were divided into sterilized 2R glass vials (0.9 g of formulation per vial), sealed and placed in a controlled environment storage cabinet at 40° C./75% RH. The headspace of the vials was ambient air to ensure forced degradation conditions, i.e., no inert atmosphere such as nitrogen was introduced. Both formulations also contained 5 ppm Fe³⁺ to enhance the oxidative stress conditions. At predefined sampling points (up to two months of storage) two vials of each formulation were withdrawn from the controlled environment cabinets, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 15 OXY(Cl) containing lipid formulation compositions (in wt %) without and with EDTA. The SPC/GDO weight ratio is 50/50 in all formulations. Sample ID OXY(Cl) SPC + GDO EtOH DMSO EDTA ETA FeCl₃ × 6H₂O* Sample 95 1.00 78.99758 10.00 10.00 — — 0.00242 Sample 96 1.00 78.97918 10.00 10.00 0.01 0.0084 0.00242 *0.00242 wt % of FeCl₃ × 6H₂O corresponds to 5 ppm of Fe³⁺

FIG. 11 presents the assay and Stability Index values of O×Y as a function of time, respectively. As evident, the use of 100 ppm EDTA solubilized in the lipid formulation with the help of ETA significantly enhanced the peptide stability in the presence of 5 ppm Fe³⁺. The data indicate that EDTA provides protection of the peptide towards low to moderate levels of metals that may originate from the excipients, the API or the processing equipment.

Example 16. Stability of GRN(0) in Lipid Formulations in the Presence of EDTA and Iron

Lipid formulations containing GRN(0) in the absence and presence of 100 ppm EDTA were prepared according to the compositions given in

Table 16. Formulations were divided into sterilized 2R glass vials (1 g of formulation per vial), sealed and placed in a controlled environment storage cabinet at 40° C./75% RH. The headspace of the vials was ambient air to ensure forced degradation conditions, i.e., no inert atmosphere such as nitrogen was introduced. Both formulations also contained 5 ppm Fe³⁺ to ensure additional oxidative stress conditions. At predefined sampling points (up to two months of storage) two vials of each formulation were withdrawn from the controlled environment cabinets, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 16 GRN(0) containing lipid formulation compositions (in wt %) without and with EDTA. When corrected to assay and water content, the GRN concentration is 9.94 mg/g in all formulations. The SPC/GDO weight ratio is 50/50 in all formulations. Sample ID GRN(0) SPC + GDO EtOH DMSO EDTA ETA FeCl₃ × 6H₂O* Sample 97 1.00 78.99758 5.00 15.00 — — 0.00242 Sample 98 1.00 78.97918 5.00 15.00 0.01 0.0084 0.00242 *0.00242 wt % of FeCl₃ × 6H₂O corresponds to 5 ppm of Fe³⁺

FIG. 12 presents assay and Stability Index values of GRN as a function of time, respectively. As evident, 100 ppm EDTA solubilized in the lipid formulation with the help of ETA significantly enhanced the stability of GRN in the presence of 5 ppm Fe³⁺. The data indicate that EDTA provides protection of the active substance towards low to moderate levels of metals that may originate from the excipients, the API or the processing equipment.

Example 17. Stability of GOS(CI) in Phospholipid/Monoglyceride (SPC/GMO) and Phospholipid/Triglyceride (SPC/SbOil) Based Formulations in the Presence of EDTA and Iron

Lipid formulations containing GOS(CL) in the absence and presence of 100 ppm EDTA were prepared according to the compositions given in

Table 17. Formulations were divided into sterilized 2R glass vials (1 g of formulation per vial), sealed and placed in controlled environment storage cabinet at 40° C./75% RH. The headspace of the vials was ambient air to ensure forced degradation conditions, i.e., no inert atmosphere such as nitrogen was introduced. All formulations also contained 5 ppm Fe³⁺ to enhance the oxidative stress conditions. At predefined sampling points (up to 9 weeks of storage) two vials of each formulation were withdrawn from the controlled environment cabinets, equilibrated to room temperature for 1 hour and analyzed for peptide content (assay) using gradient HPLC with UV detection.

TABLE 17 GOS(Cl) containing lipid formulation compositions (in wt %) without and with EDTA. The SPC/GMO and SPC/SbOil weight ratios were 50/50 in all formulations. Sample ID GOS(Cl) SPC + GMO SPC + SbOil EtOH DMSO EDTA ETA FeCl₃ × 6H₂O* Sample 99 1.00 83.99758 — 10 5 — — 0.00242 Sample 100 1.00 83.97918 — 10 5 0.01 0.0084 0.00242 Sample 101 1.00 — 83.99758 10 5 — — 0.00242 Sample 102 1.00 — 83.97918 10 5 0.01 0.0084 0.00242 *0.00242 wt % of FeCl₃ × 6H₂O corresponds to 5 ppm of Fe³⁺

FIG. 13 and FIG. 14 present the assay and Stability Index values of GOS solubilized in either SPC/GMO or SPC/SbOil based formulations as a function of time, respectively. As shown, 100 ppm EDTA solubilized in both formulation concepts with the help of ETA significantly enhanced the peptide stability in the presence of 5 ppm Fe³⁺. The data indicate that EDTA provides protection of the peptide towards low to moderate levels of metals that may originate from the excipients, the API or the processing equipment.

Example 18. Lipid Oxidation in Placebo Lipid Formulations in the Presence of EDTA

Lipid placebo formulations in the absence and presence of 100 ppm EDTA were prepared according to the compositions given in Table 18. Formulations were divided into sterilized 2R glass vials (1 g of formulation per vial), sealed and placed in controlled environment storage cabinets at either 60° C./ambient RH or 40° C./75% RH. The headspace of the vials was ambient air to ensure forced lipid oxidation conditions, i.e., no inert atmosphere such as nitrogen was introduced. Some formulations also contained 5 ppm Fe³⁺ to enhance the oxidative stress conditions (Table 18). At predefined sampling points (up to 9 days of storage at 60° C./ambient RH and up to 30 days of storage at 40° C./75% RH) two vials of each formulation were withdrawn from the controlled environment cabinets, equilibrated to room temperature for 1 hour and analyzed for oxygen concentration in the vial headspace (oxygen consumption is here used as an indirect measure of lipid oxidation in the lipid formulations) using a needle-type oxygen microsensor.

TABLE 18 Lipid formulation compositions (in wt %) without and with EDTA. The SPC/GDO weight ratio was 50/50 and 35/65 in Samples 103-106 and Samples 107-110, respectively. Sample ID SPC GDO EtOH EDTA ETA* FeCl₃ × 6H₂O** Sample 103 45.00 45.00 10 — — — Sample 104 45.00 45.00 10 — — 0.00242 Sample 105 44.99 44.99 10 0.01 0.0116 — Sample 106 44.99 44.99 10 0.01 0.0116 0.00242 Sample 107 31.50 58.50 10 — — — Sample 108 31.50 58.50 10 — — 0.00242 Sample 109 31.49 58.49 10 0.01 0.0116 — Sample 110 31.49 58.49 10 0.01 0.0116 0.00242 *ETA:EDTA molar ratio is 5.5:1 **0.00242 wt % of FeCl₃ × 6H₂O corresponds to 5 ppm of Fe³⁺

The obtained results are summarized in FIG. 15, FIG. 16, FIG. 17 and FIG. 18. The data in the figures clearly show that, independent of storage condition, lipid ratio used to prepare formulations or the presence of Fe³⁺, addition of 100 ppm of EDTA drastically reduce consumption of oxygen (and thus lipid oxidation degradation) in all formulations. The data indicate that EDTA provides protection of the lipids towards low to moderate levels of metals that may originate from the excipients or the processing equipment.

Example 19. DTPA Solubility as a Function of ETA/DTPA Molar Ratio

0.08 wt % DTPA solutions in EtOH/PG (50/50 w/w) were prepared in the absence and presence of various amounts of ETA added at different ETA/DTPA molar ratios (Table 19). The results show that DTPA is not soluble in EtOH/PG without using ETA. The obtained results also show that about 4.3 mol of ETA per 1 mol of DTPA is close to the required minimum amount needed to solubilize DTPA in the non-aqueous solvent used.

TABLE 19 Solubility of 0.08 wt % DTPA in EtOH/PG as a function of ETA/DTPA molar ratio. ETA/DTPA DTPA solubility Sample ID (mol/mol) (ca 24 h mixing) Sample 111 0.0 Not soluble Sample 112 1.7 Not soluble Sample 113 4.3 Soluble Sample 114 4.8 Soluble Sample 115 6.2 Soluble Sample 116 7.9 Soluble 

1. A mixture of: i) at least one lipid and/or at least one oil; and ii) an alkyl ammonium EDTA salt comprising an anion of ethylenediaminetetraacetic acid or an analogue thereof; wherein the mixture has a water content in the range of 0 to 1.0 wt %.
 2. (canceled)
 3. A mixture of claim 1 which is a pre-formulation comprising: i) a lipid mixture comprising: a) at least one of a mono-, di- or tri-acyl lipid and/or a tocopherol; b) optionally at least one phospholipid; c) at least one biocompatible, organic solvent; and ii) an alkyl ammonium EDTA salt comprising an anion of ethylenediaminetetraacetic acid or an analogue thereof; wherein the pre-formulation has a water content in the range of 0 to 1.0 wt %.
 4. A pre-formulation of claim 3 wherein component a) comprises a diacyl or monoacyl lipid.
 5. (canceled)
 6. A pre-formulation of claim 3 wherein component b) comprises a phosphatidyl choline (PC), a phosphatidyl ethanolamine (PE) or a phosphatidyl inositol (PI).
 7. A pre-formulation of claim 3 wherein the alkylammonium EDTA salt comprises at least one alkyl ammonium cation of formula NR¹R²R³R^(4n+); in which n is 1 to 4; wherein each R¹-R⁴ is independently H, or linear or branched C1-10 alkyl, with the proviso that at least one of R¹-R⁴ is not H; wherein each R¹-R⁴ may optionally be substituted with one or more OH or NH₂ groups.
 8. A pre-formulation of claim 3 wherein the alkylammonium EDTA salt is a salt of ethanolamine (ETA) and EDTA.
 9. A pre-formulation of claim 8 wherein the equivalents of ETA relative to the amount of EDTA is in the range of 3.5 to 7 (mol/mol).
 10. (canceled)
 11. (canceled)
 12. A pre-formulation of claim 3 wherein the alkyl ammonium EDTA salt is present in an amount of 0.001 to 0.050 wt % of the pre-formulation (10-500 ppm) based on the amount of EDTA free acid.
 13. A pre-formulation of claim 3 wherein component (ii) comprises an alkylammonium counterion having only one amino or alkylamino group and wherein the ratio of EDTA:the total of the alkylammonium counterion and any amine free base thereof in the pre-formulation is 1:≥3.0.
 14. A pre-formulation of claim 3 wherein component (ii) comprises an alkylammonium counterion having two or more amino and/or alkylamino groups, wherein the ratio of EDTA:the total of the alkylammonium counterion and any amine free base thereof in the pre-formulation is 1:≥2.0.
 15. (canceled)
 16. (canceled)
 17. A pre-formulation of claim 3 further comprising an active agent (d).
 18. A pre-formulation of claim 17 wherein the active agent (d) comprises a peptide, protein and nucleic acid based active agents, hormones, and other naturally occurring agents in their native or modified forms.
 19. (canceled)
 20. A pre-formulation of claim 17 wherein the active agent (d) comprises endogenous GLP-1, or a GLP-1 receptor agonist, or a salt thereof.
 21. (canceled)
 22. (canceled)
 23. A pre-formulation of claim 3 wherein component c) comprises at least one solvent selected from the group consisting of: alcohols, amines, amides and esters.
 24. (canceled)
 25. (canceled)
 26. A pre-formulation of claim 23 wherein component c) comprises ethanol or mixtures of ethanol and propylene glycol.
 27. (canceled)
 28. (canceled)
 29. (canceled)
 30. (canceled)
 31. (canceled)
 32. (canceled)
 33. (canceled)
 34. A composition formed by exposure of a pre-formulation according to claim 3 with excess aqueous fluid having a liquid crystalline phase structure.
 35. (canceled)
 36. A medicament comprising the pre-formulation of claim
 3. 37. A method for the treatment of a human or non-human mammalian subject comprising administering to the subject a pre-formulation of claim
 3. 38. The method of claim 37, wherein the pre-formulation is administered to the human or non-human mammalian subject in need thereof to treat at least one condition selected from acromegaly, cancers, carcinomas, melanomas, tumours expressing at least one somatostatin receptor, sst(2)-positive tumours, sst(5)-positive tumours, prostate cancers, gastro-entero-pancreatic endocrine tumours, gastro-entero-pancreatic neuroendocrine (GEP NE) tumours, carcinoid tumours, insulinomas, gastrinomas, vasoactive intestinal peptide (VIP) tumours and glucagonomas, TSH-secreting pituitary adenomas, elevated growth hormone (GH), elevated insulin-like growth factor I (IGF-I), varicial bleeding, chemotherapy induced gastro intestinal problems, lymphorrhea, diabetic retinopathy, thyroid eye disease, obesity, pancreatitis, and related conditions.
 39. A method of cosmetic treatment of a human or non-human mammalian subject comprising administering to the subject a pre-formulation of claim
 3. 40. (canceled)
 41. A method to improve the resistance to oxidation of a mixture comprising at least one lipid and/or at least one oil, the mixture having a water content in the range of 0 to 1.0 wt %.
 42. (canceled)
 43. (canceled)
 44. (canceled)
 45. (canceled)
 46. (canceled)
 47. A pre-filled administration device containing a pre-formulation of claim
 3. 48. A kit comprising an administration device of claim
 47. 49. (canceled)
 50. (canceled)
 51. A method of reducing oxidation of at least one active agent in a pre-formulation comprising: i) a lipid mixture comprising: a) at least one of a mono-, di- or tri-acyl lipid and/or a tocopherol; b) optionally at least one phospholipid; c) at least one biocompatible, organic solvent; and d) at least one active agent; wherein the pre-formulation has a water content in the range of 0 to 1.0 wt %; the method comprising including an alkylammonium EDTA salt in the pre-formulation.
 52. (canceled)
 53. A process for preparing a pre-formulation of claim 3: dispersing EDTA or a hydrate thereof and an alkylamine in a biocompatible organic solvent to produce a dispersion; mixing the dispersion until the EDTA and alkylamine are fully dissolved to produce a mixture; and adding at least one mono-, di- or tri-acyl lipid and/or a tocopherol, optionally at least one phospholipid, and at least one active agent to the mixture to produce the pre-formulation.
 54. (canceled) 